SVG Tiny 1.2 – 20080912

13 Interactivity

Contents

13.1 Introduction

SVG content can be interactive (i.e., responsive to user-initiated events) by utilizing the following features in the SVG language:

This chapter describes:

Related information can be found in other chapters:

13.2 Complete list of supported events

The following aspects of SVG are affected by events:

The following table lists all of the events which must be recognized and supported in SVG. The 'description' column describes the required conditions for the event to occur.

Event Type Description Animation event name Bubbles Cancelable uDOM interface
DOMFocusIn

Occurs when an element receives focus.

See the DOM 2 Events definition of DOMFocusIn ([DOM2EVENTS], section 1.6.1).

focusin Yes No UIEvent
DOMFocusOut

Occurs when an element loses focus.

See the DOM 2 Events definition of DOMFocusOut ([DOM2EVENTS], section 1.6.1).

focusout Yes No UIEvent
DOMActivate

Occurs when an element is activated, for instance, through a mouse click or a keypress.

See the DOM 2 Events definition of DOMActivate ([DOM2EVENTS], section 1.6.1).

activate Yes Yes UIEvent
click

Occurs when the pointing device button is clicked over an element. A click is defined as a mousedown and mouseup over the same screen location. The sequence of these events is: mousedown, mouseup, click. If multiple clicks occur at the same screen location, the sequence repeats with the detail attribute incrementing with each repetition.

See the DOM 2 Events definition of click ([DOM2EVENTS], section 1.6.2).

click Yes Yes MouseEvent
mousedown

Occurs when the pointing device button is pressed over an element.

See the DOM 2 Events definition of mousedown ([DOM2EVENTS], section 1.6.2).

mousedown Yes Yes MouseEvent
mouseup

Occurs when the pointing device button is released over an element.

See the DOM 2 Events definition of mouseup ([DOM2EVENTS], section 1.6.2).

mouseup Yes Yes MouseEvent
mouseover

Occurs when the pointing device is moved onto an element.

See the DOM 2 Events definition of mouseover ([DOM2EVENTS], section 1.6.2).

mouseover Yes Yes MouseEvent
mousemove

Occurs when the pointing device is moved while it is over an element.

See the DOM 2 Events definition of mousemove ([DOM2EVENTS], section 1.6.2).

mousemove Yes Yes MouseEvent
mouseout

Occurs when the pointing device is moved away from an element.

See the DOM 2 Events definition of mouseout ([DOM2EVENTS], section 1.6.2).

mouseout Yes Yes MouseEvent
mousewheel

Occurs when a rotational input device has been activated.

See the description of the MouseWheelEvent event for details.

none Yes Yes MouseWheelEvent
textInput

One or more characters have been entered.

See the Text events section below for details.

none Yes Yes TextEvent
keydown

A key is pressed down.

See the Key events section below for details.

none Yes Yes KeyboardEvent
keyup

A key is released.

See the Key events section below for details.

none Yes Yes KeyboardEvent
load

The event is triggered at the point at which the user agent finishes loading the element and any dependent resources (such as images, style sheets, or scripts). In the case the element references a script, the event will be raised only after an attempt to interpret the script has been made. Dependent resources that fail to load will not prevent this event from firing if the element that referenced them is still in the document tree unless they are designated as externalResourcesRequired. The event is independent of the means by which the element was added to DOM tree.

load No No Event
SVGLoad

This event is deprecated and is for backwards compatibility only, see notes below. The This event must be dispatched immediately after the load event is dispatched.

none No No Event
resize

Occurs when a document view is being resized. This event is only applicable to 'svg' elements and is dispatched after the resize operation has taken place. The target of the event is the 'svg' element.

resize Yes No Event
SVGResize

This event is deprecated and is for backwards compatibility only, see notes below. This event must be dispatched immediately after the resize event is dispatched.

none Yes No Event
scroll

Occurs when a document view is being shifted along the X or Y or both axis, either through a direct user interaction or any change on the currentTranslate property available on SVGSVGElement interface. This event is only applicable to 'svg' elements and is dispatched after the shift modification has taken place. The target of the event is the 'svg' element.

scroll Yes No Event
SVGScroll

This event is deprecated and is for backwards compatibility only, see notes below. This event must be dispatched immediately after the scroll event is dispatched.

none Yes No Event
SVGZoom

Occurs when the zoom level of a document view is being changed, either through a direct user interaction or any change to the currentScale property available on SVGSVGElement interface. This event is only applicable to 'svg' elements and is dispatched after the zoom level modification has taken place. The target of the event is the 'svg' element.

zoom No No Event
SVGRotate

Occurs when the rotation of a document view is being changed, either through a direct user interaction or any change to the currentRotate property available on SVGSVGElement interface. This event is only applicable to 'svg' elements and is dispatched after the rotation modification has taken place. The target of the event is the 'svg' element.

rotate No No Event
beginEvent

Occurs when a timed element begins.

See the SMIL 2.1 definition of beginEvent ([DOM2EVENTS], section 10.6.2).

beginEvent Yes No TimeEvent
endEvent

Occurs when a timed element ends.

See the SMIL 2.1 definition of endEvent ([DOM2EVENTS], section 10.6.2).

endEvent Yes No TimeEvent
repeatEvent

Occurs when a timed element repeats. It is raised each time the element repeats, after the first iteration.

See the SMIL 2.1 definition of repeatEvent ([DOM2EVENTS], section 10.6.2).

repeatEvent Yes No TimeEvent
loadstart

A load operation has begun.

See the description of the ProgressEvent interface for details on this event.

none No No ProgressEvent
progress

Progress has occurred in loading a given resource.

See the description of the ProgressEvent interface for details on this event.

none No No ProgressEvent
loadend

A load operation has completed.

See the description of the ProgressEvent interface for details on this event.

none No No ProgressEvent
SVGTimer

Occurs when the specified timer interval has elapsed for a timer. This event is triggered only by 'running' timers in the current global execution context of the SVG document (i.e. for timers which have been instantiated via the SVGGlobal interface and started via the start() method of the SVGTimer interface). The target of the event is the SVGTimer object itself. The event processing is limited to the at target phase.

See the description of the SVGTimer interface for more details.

none No No Event

Note that in order to unify event names with other W3C specifications, SVG Tiny 1.2 deprecates some of the SVG 1.1 event types. (The term "deprecate" in this case means that user agents which are compatible with both SVG 1.1 and SVG Tiny 1.2 must support both the old deprecated event names and the new event names. Content creators who are making content that targets SVG Tiny 1.2 should use the new event types, not the deprecated event types.) Specifically:

Details on the values of attributes on the event object passed to event listeners for the event types defined in DOM Level 2 Events can be found in the description for that event in that specification. For other event types, the values of the attributes are are described elsewhere in this specification.

13.3 User interface events

On SVG user agents which support interactivity, it is common for authors to define SVG documents such that they are responsive to user interface events. Among the set of possible user events are pointer events, keyboard events, and document events.

In response to user interface (UI) events, the author might start an animation, perform a hyperlink to another Web page, highlight part of the document (e.g. change the color of the graphics elements which are under the pointer), initiate a "roll-over" (e.g., cause some previously hidden graphics elements to appear near the pointer) or launch a script which communicates with a remote database.

The following example shows the use of a DOMActivate event to trigger an ECMAScript event handler:

Example: activate.svg
<?xml version="1.0" encoding="UTF-8"?>
<svg width="6cm" height="5cm" viewBox="0 0 600 500" xmlns="http://www.w3.org/2000/svg" version="1.2"
    baseProfile="tiny" xmlns:ev="http://www.w3.org/2001/xml-events">
    <desc>Example: invoke an ECMAScript function from a DOMActivate event </desc>
    <!-- ECMAScript to change the radius -->
    <script type="application/ecmascript">
        <![CDATA[
     function change(evt) {
       var circle = evt.target;
       var currentRadius = circle.getFloatTrait("r");
       if (currentRadius == 100)
         circle.setFloatTrait("r", currentRadius*2);
       else
         circle.setFloatTrait("r", currentRadius*0.5);
     }
   ]]>
    </script>
    <!-- Act on each DOMActivate event -->
    <circle cx="300" cy="225" r="100" fill="red">
        <handler type="application/ecmascript" ev:event="DOMActivate"> change(evt); </handler>
    </circle>
    <text x="300" y="480" font-family="Verdana" font-size="35" text-anchor="middle"> Activate the
        circle to change its size </text>
</svg>

13.4 Pointer events

Note: The W3C's Web Content Accessibility Guidelines (WCAG) advise content creators to create device-independent content; in particular, content should not require that the user has access to a pointer device.

User interface events that occur because of user actions performed on a pointer device are called pointer events.

Many systems support pointer devices such as a mouse, trackball, stylus or joypad. On systems which use a mouse, pointer events consist of actions such as mouse movements and mouse clicks. On systems with a different pointer device, the pointing device often emulates the behavior of the mouse by providing a mechanism for equivalent user actions, such as a button to press which is equivalent to a mouse click.

One difference between stylus-based pointers and mouse-based pointers is that for a mouse, the cursor always has a position; for a stylus which may be lifted, the cursor may only have a position when the stylus is tapped on the screen. Thus, content which assumes that all pointer devices will generate mouseover and mouseout events will not work on all devices.

13.5 Text events

User interface events that occur because of user actions that generate text are called text events. They are usually generated by a keyboard, but can also be generated by a different input method such as an IME (for Japanese text, for example), by speech input, etc. The event is dispatched whenever a string of Unicode characters is sent to the document and is thus independent of the input device or method used.

13.6 Key events

Note: The W3C's Web Content Accessibility Guidelines (WCAG) advise content creators to create device-independent content; in particular, content should not require that the user has access to a (full-size) keyboard.

User interface events that occur because of user actions that generate key presses (as opposed to text — for example, function keys, key presses for a game, etc.) are called key events.

13.7 Event flow

DOM Level 2 Events defines the event flow model ([DOM2EVENTS], section 1.2), which defines three phases in which event listeners in the document are triggered: capture, at target and bubbling. An SVG Tiny 1.2 user agent is not required to support the capture phase of the event flow model. If the capture phase is not supported:

13.8 Event dispatching

For each pointer event, text event or key event, the SVG user agent determines the target object of a given event. The target object must be the topmost graphics element or SVGElementInstance object whose relevant graphical content is under the pointer (for pointer events) or has focus (for text and key events) at the time of the event. (See property 'pointer-events' for a description of how to determine whether an element's relevant graphical content is under the pointer, and thus in which circumstances that graphics element can be the target object for a pointer event.) When an element is not displayed (i.e., when the 'display' property on that element or one of its ancestors has a value of none), that element must not be the target of pointer events. If the user agent cannot find a graphics element or SVGElementInstance object to be the target object (e.g., the pointer event occurs over the viewport background), then the user agent must set the target object to be the rootmost 'svg' element.

The decision on whether to dispatch the event to the target object or to one of the target elements ancestors shall depend on the following:

If an event is defined to bubble ([DOM2EVENTS], section 1.2.3), bubbling occurs up to all direct ancestors of the target object. Descendant elements receive events before their ancestors. Thus, if a 'path' element is a child of a 'g' element and they both have event listeners for click events, then the event will be dispatched to the 'path' element before the 'g' element.

After an event is initially dispatched to a particular element, unless an appropriate action has been taken to prevent further processing, the event must be passed to the appropriate event handlers (if any) for that element's ancestors (in the case of event bubbling) for further processing.

13.9 Processing order for user interface events

The processing order for user interface events shall be as follows:

The use element creates shadow content which can be the target of user interface events.

User interface events within the shadow content shall participate in the processing of user interface events in the same manner as if the shadow content were part of the main document. In other words, if shadow content contains a graphics element that renders above other content at the current pointer location, then it represents the topmost graphics element and will receive the pointer events before other elements. In this case, the user interface events bubble up through the target's ancestors, and then across the document border into the referencing element, and then through the ancestors of the referencing element. This process continues as necessary if there are multiple levels of nested shadow trees.

13.10 The 'pointer-events' property

In different circumstances, authors may want to control under what circumstances particular graphics element can become the target of pointer events. For example, the author might want a given element to receive pointer events only when the pointer is over the stroked perimeter of a given shape. In other cases, the author might want a given element to ignore pointer events under all circumstances so that graphics elements underneath the given element will become the target of pointer events.

For example, suppose a 'circle' with a 'stroke' of red (i.e., the outline is solid red) and a 'fill' of none (i.e., the interior is not painted) is rendered directly on top of a 'rect' with a 'fill' of blue. The author might want the 'circle' to be the target of pointer events only when the pointer is over the perimeter of the 'circle'. When the pointer is over the interior of the 'circle', the author might want the underlying 'rect' to be the target element of pointer events.

The 'pointer-events' property specifies under what circumstances a given graphics element can be the target element for a pointer event. It affects the circumstances under which the following are processed:

'pointer-events'
Value:   boundingBox | visiblePainted | visibleFill | visibleStroke | visible |
painted | fill | stroke | all | none | inherit
Initial:   visiblePainted
Applies to:   graphics elements
Inherited:   yes
Percentages:   N/A
Media:   visual
Animatable:   yes
Computed value:   Specified value, except inherit
boundingBox
The given element must be a target element for pointer events when the pointer is over the bounding box of the element.
visiblePainted
The given element must only be a target element for pointer events when the 'visibility' property is set to visible and when the pointer is over a "painted" area. The pointer is over a painted area if it is over the interior (i.e., 'fill') of the element and the 'fill' property is set to a value other than none or it is over the perimeter (i.e., 'stroke') of the element and the 'stroke' property is set to a value other than none.
visibleFill
The given element must only be a target element for pointer events when the 'visibility' property is set to visible and when the pointer is over the interior (i.e., 'fill') of the element. The value of the 'fill' property does not effect event processing.
visibleStroke
The given element must only be a target element for pointer events when the 'visibility' property is set to visible and when the pointer is over the perimeter (i.e., 'stroke') of the element. The value of the 'stroke' property does not effect event processing.
visible
The given element must only be a target element for pointer events when the 'visibility' property is set to visible and the pointer is over either the interior (i.e., 'fill') or the perimeter (i.e., 'stroke') of the element. The values of the 'fill' and 'stroke' do not effect event processing.
painted
The given element must only be a target element for pointer events when the pointer is over a "painted" area. The pointer is over a painted area if it is over the interior (i.e., 'fill') of the element and the 'fill' property is set to a value other than 'none' or it is over the perimeter (i.e., 'stroke') of the element and the 'stroke' property is set to a value other than none. The value of the 'visibility' property does not effect event processing.
fill
The given element must only be a target element for pointer events when the pointer is over the interior (i.e., 'fill') of the element. The values of the 'fill' and 'visibility' properties do not effect event processing.
stroke
The given element must only be a target element for pointer events when the pointer is over the perimeter (i.e., 'stroke') of the element. The values of the 'stroke' and 'visibility' properties do not effect event processing.
all
The given element must be a target element for pointer events whenever the pointer is over either the interior (i.e., 'fill') or the perimeter (i.e., 'stroke') of the element. The values of the 'fill', 'stroke' and 'visibility' properties do not effect event processing.
none
The given element must not receive pointer events.

For text elements, hit detection shall be performed on a character cell basis:

For raster images, hit detection shall either be performed on a whole-image basis (i.e., the rectangular area for the image is one of the determinants for whether the image receives the event) or on a per-pixel basic (i.e., the alpha values for pixels under the pointer help determine whether the image receives the event). The following rules must be adhered to:

Note that for raster images, the values of properties 'fill-opacity', 'stroke-opacity', 'fill' and 'stroke' do not effect event processing.

13.11 Magnification and panning

Magnification represents a complete, uniform transformation on an SVG document fragment, where the magnify operation scales all graphical elements by the same amount. A magnify operation has the effect of a supplemental scale and translate transformation placed at the rootmost level on the SVG document fragment (i.e. outside the rootmost 'svg' element).

Panning represents a translation (i.e., a shift) transformation on an SVG document fragment in response to a user interface action.

SVG user agents that operate in interaction-capable user environments are required to support the ability to magnify and pan.

Attribute definition:

zoomAndPan = "magnify" | "disable"
Can be specified on the 'svg' element. The attribute is intended for applications where SVG is used for both the content and for the user interface, eg a mapping application. The default zoom might move critical user interface components from view, confusing the user; disabling the default zoom, pan and rotate while providing zoom, pan and rotate controls for a smaller content area would give a better user experience.
The attribute value can be either of the following:
magnify
The lacuna value. If magnify, in environments that support user interactivity, the user agent shall provide controls to allow the user to perform a "magnify" operation on the document fragment.
disable
If disable, the user agent shall in its default interaction mode disable any magnification and panning controls and not allow the user to magnify or pan on the given document fragment. The SVG user agent may provide another mode which continues to allow zoom and pan at user option.

Animatable: No

13.12 Element focus

13.12.1 The 'focusable' attribute

In many cases, such as text editing, the user is required to place focus on a particular element, ensuring that input events, such as keyboard input, are sent to that element.

All renderable elements are required to be able to accept focus if specified by the author, including container elements (except 'defs'), graphics elements, 'tspan' and 'foreignObject'. A focusable container element may contain focusable descendants.

Attribute definition:

focusable = "true" | "false" | "auto"
Defines if an element can get keyboard focus (i.e. receive keyboard events) and be a target for field-to-field navigation actions. (Note: in some environments, field-to-field navigation can be accomplished with the tab key.)
The attribute value can be either of the following:
true
The element is keyboard-aware and must be treated as any other UI component that can get focus.
false
The element is not focusable.
auto
The lacuna value. Equivalent to false, except that it must be treated like true for the following cases:

Animatable: Yes

System-dependent input facilities (e.g., the tab key on most desktop computers) should be supported to allow navigation between elements that can obtain focus (i.e. elements for which the value of the 'focusable' attribute evaluates to "true").

The document has the concept of a focus ring, which is the order in which elements obtain focus. By default the focus ring shall be obtained using document order. All focusable elements must be part of the default focus ring. A document's focus ring includes any focusable objects within shadow trees for 'use' elements. The focus attributes may be used to modify the default focus ring.

The SVG language supports a flattened notion of field navigation between focusable elements where an author may define field navigation between any two focusable elements defined within a given SVG document without regard to document hierarchy. For example:

    <rect xml:id="r1" focusable="true".../>
    <g xml:id="g1" focusable="true">
      <circle xml:id="c1" focusable="true".../>
    </g>

In the above example, the author may specify field-to-field navigation such the user can navigate directly from any of the three elements. Thus, assuming a desktop computer which uses the tab key for field navigation, the author may specify focus navigation order such that the tab key takes the user from 'r1' to 'c1' to 'g1'.

When navigating to an element that is not visible on the canvas the following rules shall apply:

SVG's flattened notion of field navigation shall extend to referenced content and shadow trees as follows:

Focus navigation shall behave as specified:

  1. When the document is loaded the focus is first offered to the SVG user agent.
  2. Once the SVG user agent releases focus, then focus passes to the entity that first matches the following criteria:
    1. the rootmost 'svg' element if it is focusable,
    2. the element referenced by the 'nav-next' attribute on the rootmost 'svg' element, if the attribute is present,
    3. the first focusable element in the document starting from the rootmost 'svg' element,
    4. the SVG user agent
  3. If the focus is held by an element in the document, then the next element in navigation order shall be the entity that first matches the following criteria:
    1. the element referenced by the 'nav-next' attribute on the focused element,
    2. the next focusable element in document order,
    3. the SVG user agent
  4. If the focus is held by an element in the document, then the previous element in navigation order shall be the entity that first matches the following criteria:
    1. the element referenced by the 'nav-prev' attribute on the focused element,
    2. the previous focusable element in document order,
    3. the SVG user agent

For stand-alone SVG documents, the SVG user agent must always have a currently focused object. If focus is not held by any object in the document tree, the SVG user agent must give focus to the SVGDocument object.

For SVG documents which are referenced by a non-SVG host document (e.g., XHTML), the SVG document may participate within the host document's focus ring, which would allow direct navigation from an SVG focusable element onto a focusable element within the host document. Other compound document specifications may define supplemental SVG focus navigation rules for situations when SVG content is used as a component within a compound document.

User agents should provide a mechanism for a user to escape from a focus ring. When the user activates this mechanism, the user agent should change focus to the user agent, sending the appropriate focusout event to the element currently in focus.

13.13.2 Specifying navigation

Navigation order can be specified using the ten navigation attributes defined below.

nav-next

The 'nav-next' attribute specifies the next element in the focus ring.

Attribute definition:

nav-next = "url(<IRI>)" | "auto" | "self"
Specifies the next element in the focus ring.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the next direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior shall be as if the attribute was not specified (navigation must follow the rules specified in Navigation behavior).
self
The focus must stay on the element itself.

Animatable: Yes

nav-prev

The 'nav-prev' attribute specifies the previous element in the focus ring.

Attribute definition:

nav-prev = "url(<IRI>)" | "auto" | "self"
Specifies the previous element in the focus ring.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the previous direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior shall be as if the attribute was not specified (navigation must follow the rules specified in Navigation behavior).
self
The focus must stay on the element itself.

Animatable: Yes

nav-up

The 'nav-up' attribute specifies the element to be focused if a navigation in the upward direction is triggered.

Attribute definition:

nav-up = "url(<IRI>)" | "auto" | "self"
Specifies the element to receive focus in the upward direction.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the upward direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior is left up to the SVG user agent.
self
The focus must stay on the element itself.

Animatable: Yes

nav-up-right

The 'nav-up-right' attribute specifies the element to be focused if a navigation in the upward-rightward direction is triggered.

Attribute definition:

nav-up-right = "url(<IRI>)" | "auto" | "self"
Specifies the element to receive focus in the upward-rightward direction.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the upward-rightward direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior is left up to the SVG user agent.
self
The focus must stay on the element itself.

Animatable: Yes

nav-right

The 'nav-right' attribute specifies the element to be focused if a navigation in the rightward direction is triggered.

Attribute definition:

nav-right = "url(<IRI>)" | "auto" | "self"
Specifies the element to receive focus in the rightward direction.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the rightward direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior is left up to the SVG user agent.
self
The focus must stay on the element itself.

Animatable: Yes

nav-down-right

The 'nav-down-right' attribute specifies the element to be focused if a navigation in the downward-rightward direction is triggered.

Attribute definition:

nav-down-right = "url(<IRI>)" | "auto" | "self"
Specifies the element to receive focus in the downward-rightward direction.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the downward-rightward direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior is left up to the SVG user agent.
self
The focus must stay on the element itself.

Animatable: Yes

nav-down

The 'nav-down' attribute specifies the element to be focused if a navigation in the downward direction is triggered.

Attribute definition:

nav-down = "url(<IRI>)" | "auto" | "self"
Specifies the element to receive focus in the downward direction.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the downward direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior is left up to the SVG user agent.
self
The focus must stay on the element itself.

Animatable: Yes

nav-down-left

The 'nav-down-left' attribute specifies the element to be focused if a navigation in the downward-leftward direction is triggered.

Attribute definition:

nav-down-left = "url(<IRI>)" | "auto" | "self"
Specifies the element to receive focus in the downward-leftward direction.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the downward-leftward direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior is left up to the SVG user agent.
self
The focus must stay on the element itself.

Animatable: Yes

nav-left

The 'nav-left' attribute specifies the element to be focused if a navigation in the leftward direction is triggered.

Attribute definition:

nav-left = "url(<IRI>)" | "auto" | "self"
Specifies the element to receive focus in the leftward direction.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the leftward direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior is left up to the SVG user agent.
self
The focus must stay on the element itself.

Animatable: Yes

nav-up-left

The 'nav-up-left' attribute specifies the element to be focused if a navigation in the upward-leftward direction is triggered.

Attribute definition:

nav-up-left = "url(<IRI>)" | "auto" | "self"
Specifies the element to receive focus in the upward-leftward direction.
The attribute value can be either of the following:
url(<IRI>)
Specifies the element that must receive focus when navigation in the upward-leftward direction is triggered. The specified element must be within the Current SVG Document Fragment.
auto
The lacuna value. Means that the behavior is left up to the SVG user agent.
self
The focus must stay on the element itself.

Animatable: Yes
Example: navigation.svg
<?xml version="1.0"?>

<svg viewBox="0 0 220 40" 
	xmlns="http://www.w3.org/2000/svg"
	xmlns:xlink="http://www.w3.org/1999/xlink"
	version="1.2" baseProfile="tiny">
     
  <desc>An example which illustrates the use of nav-* attributes</desc>

	<!-- List of available channels -->
	<rect x="0" y="0" width="100" height="20" fill="#fb0" stroke="#000" stroke-width="2" />
	<text x="50" y="13" font-size="8" font-family="Arial Black"  
	      fill="#fff" text-anchor="middle" >Channel 1</text>
	<rect x="0" y="20" width="100" height="20" fill="#fb0" stroke="#000" stroke-width="2" />
	<text x="50" y="33" font-size="8" font-family="Arial Black" 
	      fill="#fff" text-anchor="middle" >Channel 2</text>
	<rect x="0" y="40" width="100" height="20" fill="#fb0" stroke="#000" stroke-width="2" />
	<text x="50" y="53" font-size="8" font-family="Arial Black" 
	      fill="#fff" text-anchor="middle" >Channel 3</text>

	<!-- List of programs for channel nb 1 -->
	<g xml:id="Chan1Prog1" focusable="true" nav-left="self" nav-right="url(#Chan1Prog2)" 
	   nav-up="self" nav-down="url(#Chan2Prog1)">
	  <rect x="100" y="0" width="100" height="20" fill="#fd0" stroke="#000" stroke-width="2">
		<set attributeName="fill" begin="Chan1Prog1.focusin" end="Chan1Prog1.focusout" to="#fa0"/>
	  </rect>
	  <text x="150" y="13" font-size="8" font-family="Arial Black" 
	        fill="#fff" text-anchor="middle" >Weather</text>
	</g>
	<g xml:id="Chan1Prog2" focusable="true" nav-left="url(#Chan1Prog1)" nav-right="url(#Chan1Prog3)" 
	   nav-up="self" nav-down="auto">
	  <rect x="200" y="0" width="120" height="20" fill="#fd0" stroke="#000" stroke-width="2">
		<set attributeName="fill" begin="Chan1Prog2.focusin" end="Chan1Prog2.focusout" to="#fa0"/>
	  </rect>
	  <text x="260" y="13" font-size="8" font-family="Arial Black" 
	        fill="#fff" text-anchor="middle" >The news</text>
	</g>
	<g xml:id="Chan1Prog3" focusable="true" nav-left="url(#Chan1Prog2)" nav-right="self" nav-up="self" 
	   nav-down="auto" nav-next="self">
	  <rect x="320" y="0" width="120" height="20" fill="#fd0" stroke="#000" stroke-width="2">
		<set attributeName="fill" begin="Chan1Prog3.focusin" end="Chan1Prog3.focusout" to="#fa0"/>
	  </rect>
	  <text x="380" y="13" font-size="8" font-family="Arial Black" 
	        fill="#fff" text-anchor="middle" >Football</text>
	</g>

	<!-- List of programs for channel nb 2 -->
	<g xml:id="Chan2Prog1" focusable="true" nav-left="self" nav-right="auto" nav-up="url(#Chan1Prog1)" 
	   nav-down="auto" nav-prev="url(#Chan1Prog1)" nav-next="auto">
	  <rect x="100" y="20" width="150" height="20" fill="#fd0" stroke="#000" stroke-width="2">
		<set attributeName="fill" begin="Chan2Prog1.focusin" end="Chan2Prog1.focusout" to="#fa0"/>
	  </rect>
	  <text x="175" y="33" font-size="8" font-family="Arial Black" 
	        fill="#fff" text-anchor="middle" >Long Movie</text>
	</g> 
</svg>

This example illustrates how it is possible for an author to control the focus order between several focusable elements displayed on the canvas.

On a device which provides a 2-way navigation system (a TAB mechanism for instance), here are the interesting behaviors:

On a device which provides a 4-way navigation system (i.e. a joystick for instance), here are the interesting behaviors:

13.13.3 Specifying focus highlighting

Automated highlighting upon focus can be specified using the 'focusHighlight' attribute. This hint indicates whether the SVG user agent should highlight an element on focus. The highlighting method is implementation dependent and the SVG user agent should pick a method that works well for varying content. This attribute is available on all graphical and container elements.

focusHighlight = "auto" | "none"
Specifies whether a SVG user agent should highlight an element on focus.
The attribute value can be either of the following:
auto
The lacuna value. This indicates that the element should be highlighted on focus. The highlighting method is left up to the SVG user agent.
none
The SVG user agent should not highlight this element on focus.

Animatable: No
Example: focusHighlight.svg
<?xml version="1.0"?>

<svg viewBox="0 0 210 80" 
	xmlns="http://www.w3.org/2000/svg"
	xmlns:xlink="http://www.w3.org/1999/xlink"
	version="1.2" baseProfile="tiny">
  
  <desc>An example which illustrates the use of focusHighlight attribute</desc>

	<text x="5" y="10">Do you want to validate transaction ?</text>
	<text x="5" y="25">You may read <a xlink:href="http://www.example.org/pay"
	                     >this</a> and <a xlink:href="http://www.example.org/infos">that</a>
	</text>
	
	<a xml:id="ValidateButton" transform="translate(5,40)" focusHighlight="none" xlink:href="validate.htm">
		<rect x="0" y="0" width="90" height="20" fill="#0f0" stroke="#000" stroke-width="2">
			<set attributeName="fill" begin="ValidateButton.focusin" end="ValidateButton.focusout" to="#0a0"/>
		</rect>
		<text x="45" y="13" font-size="8" font-family="Arial Black"  
		      fill="#000" text-anchor="middle">Validate</text>
	</a>
	<a xml:id="AbortButton" transform="translate(100,40)" focusHighlight="none" xlink:href="abort.htm">
		<rect x="0" y="0" width="90" height="20" fill="#f00" stroke="#000" stroke-width="2">
			<set attributeName="fill" begin="AbortButton.focusin" end="AbortButton.focusout" to="#a00"/>
		</rect>
		<text x="45" y="13" font-size="8" font-family="Arial Black" 
		      fill="#000" text-anchor="middle">Abort</text>
	</a>

</svg>
Rendering of focusHighlight.svg

In the above SVG example:

13.13.4 Obtaining and listening to focus programmatically

When the user agent gives an element focus it receives a DOMFocusIn event which has the new focused object as the event target and a DOMFocusOut event which has the previously focused object as the event target.

The SVGSVGElement interface has a setFocus method that puts the focus on the requested object. Calling setFocus with an element that is not focusable causes focus to stay on the currently focused object.

The SVGSVGElement interface has a moveFocus(short motionType) which moves current focus to a different object based on the value of motionType.

SVG user agents which support pointer devices such as a mouse must allow users to put focus onto focusable elements. For example, it should be possible to click on a focusable element in order to give focus.

Empty text fields in SVG theoretically take up no space, but they have a point or zero-width line segment that represents the location of the empty text field. SVG user agents should allow users with pointer devices to put focus into empty text fields by initiating a select action (e.g., a mouse click) at the location of the empty text field.

An author may change the field navigation order from a script by using the setTrait method to change the current value of navigation attributes on a given element (see Example below).

Example: changeNavigationOrder.svg
<?xml version="1.0"?>

<svg xmlns="http://www.w3.org/2000/svg" version="1.2" baseProfile="tiny"
     xmlns:ev="http://www.w3.org/2001/xml-events">
     
  <desc>An example of how to change the navigation order from script by
  changing nav-* attribute values. In this example, "myRect2" disappears between 10 and 20 sec 
  and is replaced by the "myRectNew" rectangle during this period. Consequently, the navigation order 
  must be changed accordingly during this period and we must re-established initial order after 20s.</desc>

  <rect xml:id="myRect1" x="10" y="20" width="100" height="50" fill="red" focusable="true" nav-right="url(#myRect2)">
        <set begin="focusin" end="focusout" attributeName="fill" to="purple"/>
  </rect>

  <rect xml:id="myRect2" x="120" y="20" width="100" height="50" fill="red" focusable="true" 
        nav-right="url(#myRect3)" nav-left="url(#myRect1)">
        <set begin="focusin" end="focusout" attributeName="fill" to="purple"/>
        <set begin="0"  end="10" attributeName="display" to="inline"/>
        <set begin="10" end="20" attributeName="display" to="none"/>
        <set begin="20"          attributeName="display" to="inline"/>
  </rect>
  <rect xml:id="myRect3" x="230" y="20" width="100" height="50" fill="red" focusable="true" nav-left="url(#myRect2)">
        <set begin="focusin" end="focusout" attributeName="fill" to="purple"/>
  </rect>

  <rect xml:id="myRectNew" x="120" y="20" width="100" height="50" fill="blue" focusable="true" nav-right="url(#myRect3)" 
        nav-left="url(#myRect1)" display="none" >
        <set xml:id="myRectNewFillAnim"    begin="focusin" end="focusout" attributeName="fill"    to="black"/>
        <set xml:id="myRectNewDisplayAnim" begin="10"      end="20"       attributeName="display" to="inline"/>
  </rect>

  <!-- register a listener for myRectNew.beginEvent event -->
  <ev:listener event="beginEvent" observer="myRectNew" handler="#myAnimationHandler" />
  <ev:listener event="endEvent"   observer="myRectNew" handler="#myAnimationHandler" />

  <!-- handler which is called when myRect2 is replaced by myRectNew -->
  <handler xml:id="myAnimationHandler" type="application/ecmascript"><![CDATA[
    var myRect1 = document.getElementById("myRect1");
    var myRect3 = document.getElementById("myRect3");
    
    if (evt.type == "beginEvent" && evt.target.id == "myRectNewDisplayAnim")
    {
        myRect1.setTrait("nav-right", "url(#myRectNew)");
        myRect3.setTrait("nav-left", "url(#myRectNew)");
    }
    else if (evt.type == "endEvent" && evt.target.id == "myRectNewDisplayAnim")
    {
        myRect1.setTrait("nav-right", "url(#myRect2)");
        myRect3.setTrait("nav-left", "url(#myRect2)");
    }
  ]]></handler>

</svg>