area
elementmap
element ancestor.alt
coords
shape
href
target
rel
media
hreflang
type
interface HTMLAreaElement : HTMLElement { attribute DOMString alt; attribute DOMString coords; attribute DOMString shape; stringifier attribute DOMString href; attribute DOMString target; attribute DOMString rel; readonly attribute DOMTokenList relList; attribute DOMString media; attribute DOMString hreflang; attribute DOMString type; // URL decomposition IDL attributes attribute DOMString protocol; attribute DOMString host; attribute DOMString hostname; attribute DOMString port; attribute DOMString pathname; attribute DOMString search; attribute DOMString hash; };
The area
element represents either a hyperlink with some text and a corresponding area on an image map, or a dead area on an image map.
If the area
element has an href
attribute, then the area
element represents a hyperlink. In this case, the alt
attribute must be present. It specifies the text of the hyperlink. Its value must be text that, when presented with the texts specified for the other hyperlinks of the image map, and with the alternative text of the image, but without the image itself, provides the user with the same kind of choice as the hyperlink would when used without its text but with its shape applied to the image. The alt
attribute
may be left blank if there is another area
element in the same image map that points to the same resource and has a non-blank alt
attribute.
If the area
element has no href
attribute, then the area represented by the element cannot be selected, and the alt
attribute must be omitted.
In both cases, the shape
and coords
attributes specify the area.
The shape
attribute is an enumerated attribute. The following table lists the keywords defined for this attribute. The states given in the first cell of the rows with keywords give the states to which those keywords map.
State | Keywords | |
---|---|---|
Circle state | circle |
|
Default state | default |
|
Polygon state | poly |
|
Rectangle state | rect |
|
The attribute may be omitted. The missing value default is the rectangle state.
The coords
attribute must, if specified, contain a valid list of integers. This attribute gives the coordinates for the shape described by the shape
attribute.
In the circle state, area
elements must have a coords
attribute present, with three integers, the last of which must be non-negative. The first integer must be the distance in CSS pixels from the left edge of the image to the center of the circle, the second integer must be the distance in CSS pixels from the top edge of the image to the center of the circle, and the third integer must be the radius of the circle, again in CSS pixels.
In the default state state, area
elements must not have a coords
attribute. (The area is the whole image.)
In the polygon state, area
elements must have a coords
attribute with at least six integers, and the number of integers must be even. Each pair of integers must represent a coordinate given as the distances from the left and the top of the image in CSS pixels respectively, and all the coordinates together must represent the points of the polygon, in order.
In the rectangle state, area
elements must have a coords
attribute with exactly four integers, the first of which must be less than the third, and the second of which must be less than the fourth. The four points must represent, respectively, the distance from the left edge of the image to the left side of the rectangle, the distance from the top edge to the top side, the distance from the left edge to the right side, and the distance from the top edge to the bottom side, all in CSS pixels.
The target
, rel
, media
, hreflang
, and type
attributes must be omitted if the href
attribute is not present.
The IDL attributes alt
, coords
, href
, target
, rel
, media
, hreflang
, and type
, each must reflect the respective content attributes of the same name.
The IDL attribute shape
must reflect the shape
content attribute.
The IDL attribute relList
must reflect the rel
content attribute.
The area
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same
as setting the element's href
attribute to the new output value.
An image map allows geometric areas on an image to be associated with hyperlinks.
An image, in the form of an img
element or an object
element representing an image, may be associated with an image map (in the form of a map
element) by specifying a usemap
attribute on the img
or object
element. The usemap
attribute, if specified, must be a valid hash-name reference to a map
element.
Consider an image that looks as follows:
If we wanted just the colored areas to be clickable, we could do it as follows:
<p> Please select a shape: <img src="shapes.png" usemap="#shapes" alt="Four shapes are available: a red hollow box, a green circle, a blue triangle, and a yellow four-pointed star."> <map name="shapes"> <area shape=rect coords="50,50,100,100"> <!-- the hole in the red box --> <area shape=rect coords="25,25,125,125" href="red.html" alt="Red box."> <area shape=circle coords="200,75,50" href="green.html" alt="Green circle."> <area shape=poly coords="325,25,262,125,388,125" href="blue.html" alt="Blue triangle."> <area shape=poly coords="450,25,435,60,400,75,435,90,450,125,465,90,500,75,465,60" href="yellow.html" alt="Yellow star."> </map> </p>
The math
element from the MathML namespace falls into the embedded content, phrasing content, and flow content categories for the purposes of the content models in this specification.
The semantics of MathML elements are defined by the MathML specification and other applicable specifications. [MATHML]
Here is an example of the use of MathML in an HTML document:
<!DOCTYPE html> <html> <head> <title>The quadratic formula</title> </head> <body> <h1>The quadratic formula</h1> <p> <math> <mi>x</mi> <mo>=</mo> <mfrac> <mrow> <mo form="prefix">−</mo> <mi>b</mi> <mo>±</mo> <msqrt> <msup> <mi>b</mi> <mn>2</mn> </msup> <mo>−</mo> <mn>4</mn> <mo></mo> <mi>a</mi> <mo></mo> <mi>c</mi> </msqrt> </mrow> <mrow> <mn>2</mn> <mo></mo> <mi>a</mi> </mrow> </mfrac> </math> </p> </body> </html>
The svg
element from the SVG namespace falls into the embedded content, phrasing content, and flow content categories for the purposes of the content models in this specification.
When the SVG foreignObject
element contains elements from the HTML namespace, such elements must all be flow content. [SVG]
The content model for title
elements in the SVG namespace inside HTML documents is phrasing content. (This further constrains the requirements given in the SVG specification.)
The semantics of SVG elements are defined by the SVG specification and other applicable specifications. [SVG]
The SVG specification includes requirements regarding the handling of elements in the DOM that are not in the SVG namespace, that are in SVG fragments, and that are not included in a foreignObject
element. This specification does not define any processing for elements in SVG fragments that are not in the HTML namespace; they are considered neither conforming nor non-conforming from the perspective of this specification.
The width
and height
attributes on img
, iframe
, embed
, object
, video
, and, when their type
attribute is in the Image Button state, input
elements may be specified to give the dimensions of the visual content of the element (the width and height respectively, relative to the nominal direction of the output medium), in CSS pixels. The attributes, if specified, must have values that are valid non-negative integers.
The specified dimensions given may differ from the dimensions specified in the resource itself, since the resource may have a resolution that differs from the CSS pixel resolution. (On screens, CSS pixels have a resolution of 96ppi, but in general the CSS pixel resolution depends on the reading distance.) If both attributes are specified, then one of the following statements must be true:
The target ratio is the ratio of the intrinsic width to the intrinsic height in the resource. The specified width and specified height are the values of the width
and height
attributes respectively.
The two attributes must be omitted if the resource in question does not have both an intrinsic width and an intrinsic height.
If the two attributes are both zero, it indicates that the element is not intended for the user (e.g. it might be a part of a service to count page views).
The dimension attributes are not intended to be used to stretch the image.
The width
and height
IDL attributes on the iframe
, embed
, object
, and video
elements must reflect the respective content attributes of the same name.