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18 Scripting



18.1 Specifying the scripting language

18.1.1 Specifying the default scripting language

The contentScriptType attribute on the 'svg' element specifies the default scripting language for the given document fragment.

. contentScriptType = "%ContentType;"
Identifies the default scripting language for the given document. This attribute sets the scripting language used to process the value strings in event attributes. The value %ContentType; specifies a media type, per [RFC2045]. The default value is "text/ecmascript".
Animatable: no.

18.1.2 Local declaration of a scripting language

It is also possible to specify the scripting language for each individual 'script' element by specifying a type attribute on the 'script' element.

18.2 The 'script' element

A 'script' element is equivalent to the 'script' element in HTML and thus is the place for scripts (e.g., ECMAScript). Any functions defined within any 'script' element have a "global" scope across the entire current document.

The following is an example of defining an ECMAScript function and defining an event handler that invokes that function:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20000303 Stylable//EN" 
<svg width="4in" height="3in">
    <script type="text/ecmascript"><![CDATA[
      /* Every time you click, increase the radius by 10. */
      function MouseClickHandler(MouseEvent evt) {; }
  <circle onclick="MouseClickHandler(evt)" cx="100" cy="100" r="85"/>

Download this example

<!ELEMENT script (#PCDATA) >
<!ATTLIST script
  type %ContentType; #REQUIRED
  xlink:href %URI; #IMPLIED
  externalResourcesRequired %Boolean; #IMPLIED >

Attribute definitions:

type = "%ContentType;"
Identifies the scripting language for the given 'script' element. The value %ContentType; specifies a media type, per [RFC2045]. Animatable: no.

Attributes defined elsewhere:
%stdAttrs;, %xlinkRefAttrs;, href.

18.3 Event handling

Events can cause scripts to execute when either of the following has occurred:

Related sections of the spec:

18.4 Event attributes

The following event attributes are available on many SVG elements, including its graphics elements and its container elements.

Mouse Events

Animatable: no.

Keyboard Events

Animatable: no.

State Change Events

Animatable: no.

A load event is dispatched only to the element to which the event applies; it is not dispatched to its ancestors. For example, if an 'image' element and its parent 'g' element both have event listeners for load events, when the 'image' element has been loaded, only its event listener will be invoked. (The 'g' element's event listener will indeed get invoked, but the invocation will happen when the 'g' itself has been loaded.)

Additionally, SVG's scripting engine needs to have the altKey, ctrlKey and shiftKey properties available.

18.5 DOM interfaces

The following interfaces are defined below: SVGScriptElement, SVGZoomEvent.

Interface SVGScriptElement

The SVGScriptElement interface corresponds to the 'script' element.

IDL Definition
interface SVGScriptElement : SVGElement, SVGURIReference {
           attribute DOMString language;

DOMString language
Corresponds to attribute language on the given 'script' element.

Interface SVGZoomEvent

The zoom event handler occurs before the zoom event is processed. The remainder of the DOM represents the previous state of the document. The document will be updated upon normal return from the event handler.

The UI event type for a zoom event is:

The zoom event occurs when the user initiates an action which causes the current view of the SVG document fragment to be rescaled. Event handlers are only recognized on 'svg' elements.

IDL Definition
interface SVGZoomEvent : UIEvent {
           attribute SVGRect zoomRectScreen;
           attribute float previousScale;
           attribute SVGPoint previousTranslate;
           attribute float newScale;
           attribute SVGPoint newTranslate;

SVGRect zoomRectScreen
The specified zoom rectangle in screen units.
float previousScale
The scale factor from previous zoom operations that was in place before the zoom operation occurred.
SVGPoint previousTranslate
The translation values from previous zoom operations that were in place before the zoom operation occurred.
float newScale
The scale factor that will be in place after the zoom operation has been processed.
SVGPoint newTranslate
The translation values that will be in place after the zoom operation has been processed.

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