[Exposed=Window]
interface HTMLMapElement : HTMLElement {
  [HTMLConstructor] constructor();

  [CEReactions, Reflect] attribute DOMString name;
  [SameObject] readonly attribute HTMLCollection areas;
};

The map element, in conjunction with an img element and any area element descendants, defines an image map. The element represents its children.

The name attribute gives the map a name so that it can be referenced. The attribute must be present and must have a non-empty value with no ASCII whitespace. The value of the name attribute must not be equal to the value of the name attribute of another map element in the same tree. If the id attribute is also specified, both attributes must have the same value.

map.areas: Returns an HTMLCollection of the area elements in the map.

The areas attribute must return an HTMLCollection rooted at the map element, whose filter matches only area elements.

Image maps can be defined in conjunction with other content on the page, to ease maintenance. This example is of a page with an image map at the top of the page and a corresponding set of text links at the bottom.

<!DOCTYPE HTML>
<HTML LANG="EN">
<TITLE>Babies?: Toys</TITLE>
<HEADER>
 <H1>Toys</H1>
 <IMG SRC="/images/menu.gif"
      ALT="Babies? navigation menu. Select a department to go to its page."
      USEMAP="#NAV">
</HEADER>
 ...
<FOOTER>
 <MAP NAME="NAV">
  <P>
   <A HREF="/clothes/">Clothes</A>
   <AREA ALT="Clothes" COORDS="0,0,100,50" HREF="/clothes/"> |
   <A HREF="/toys/">Toys</A>
   <AREA ALT="Toys" COORDS="100,0,200,50" HREF="/toys/"> |
   <A HREF="/food/">Food</A>
   <AREA ALT="Food" COORDS="200,0,300,50" HREF="/food/"> |
   <A HREF="/books/">Books</A>
   <AREA ALT="Books" COORDS="300,0,400,50" HREF="/books/">
  </P>
 </MAP>
</FOOTER>

4.8.13 The `area` element

Element/area

Support in all current engines.

Firefox1+Safari1+Chrome1+

Opera?Edge79+

Edge (Legacy)12+Internet ExplorerYes

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android?

HTMLAreaElement

Support in all current engines.

Firefox1+Safari1+Chrome1+

Opera12.1+Edge79+

Edge (Legacy)12+Internet Explorer5.5+

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android12.1+

HTMLAreaElement/rel

Support in all current engines.

Firefox30+Safari9+Chrome54+

Opera?Edge79+

Edge (Legacy)12+Internet Explorer11

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android?

HTMLAreaElement/relList

Support in all current engines.

Firefox30+Safari9+Chrome65+

Opera41+Edge79+

Edge (Legacy)18Internet ExplorerNo

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android41+

Categories:

Flow content.

Phrasing content.

Contexts in which this element can be used:

Where phrasing content is expected, but only if there is a map element ancestor.

Content model:

Nothing.

Tag omission in text/html:

No end tag.

Content attributes:

Global attributes

alt — Replacement text for use when images are not available

coords — Coordinates for the shape to be created in an image map

shape — The kind of shape to be created in an image map

href — Address of the hyperlink

target — Navigable for hyperlink navigation

download — Whether to download the resource instead of navigating to it, and its filename if so

ping — URLs to ping

rel — Relationship between the location in the document containing the hyperlink and the destination resource

referrerpolicy — Referrer policy for fetches initiated by the element

Accessibility considerations:

If the element has an href attribute: for authors; for implementers.

Otherwise: for authors; for implementers.

DOM interface:

[Exposed=Window]
interface HTMLAreaElement : HTMLElement {
  [HTMLConstructor] constructor();

  [CEReactions, Reflect] attribute DOMString alt;
  [CEReactions, Reflect] attribute DOMString coords;
  [CEReactions, Reflect] attribute DOMString shape;
  [CEReactions, Reflect] attribute DOMString target;
  [CEReactions, Reflect] attribute DOMString download;
  [CEReactions, Reflect] attribute USVString ping;
  [CEReactions, Reflect] attribute DOMString rel;
  [SameObject, PutForwards=value, Reflect="rel"] readonly attribute DOMTokenList relList;
  [CEReactions] attribute DOMString referrerPolicy;

  // also has obsolete members
};
HTMLAreaElement includes HTMLHyperlinkElementUtils;

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.

An area element with a parent node must have a map element ancestor.

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 with the following keywords and states:

Keyword	Conforming	State	Brief description
`circle`		Circle state	Designates a circle, using exactly three integers in the `coords` attribute.
`circ`	No	Circle state
`default`		Default state	This area is the whole image. (The `coords` attribute is not used.)
`poly`		Polygon state	Designates a polygon, using at-least six integers in the `coords` attribute.
`polygon`	No	Polygon state
`rect`		Rectangle state	Designates a rectangle, using exactly four integers in the `coords` attribute.
`rectangle`	No	Rectangle state

The attribute's missing value default and invalid value default are both the rectangle state.

The coords attribute must, if specified, contain a valid list of floating-point numbers. This attribute gives the coordinates for the shape described by the shape attribute. The processing for this attribute is described as part of the image map processing model.

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, 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.

When user agents allow users to follow hyperlinks or download hyperlinks created using the area element, the href, target, download, and ping attributes decide how the link is followed. The rel attribute may be used to indicate to the user the likely nature of the target resource before the user follows the link.

The target, download, ping, rel, and referrerpolicy attributes must be omitted if the href attribute is not present.

If the itemprop attribute is specified on an area element, then the href attribute must also be specified.

HTMLAreaElement/referrerPolicy

Support in all current engines.

Firefox50+Safari14.1+Chrome52+

Opera?Edge79+

Edge (Legacy)?Internet ExplorerNo

Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android?

The IDL attribute referrerPolicy must reflect the referrerpolicy content attribute, limited to only known values.

4.8.14 Image maps

4.8.14.1 Authoring

An image map allows geometric areas on an image to be associated with hyperlinks.

An image, in the form of an img element, may be associated with an image map (in the form of a map element) by specifying a usemap attribute on the img element. The usemap attribute, if specified, must be a valid hash-name reference to a map element.

Consider an image that looks as follows:

A line with four shapes in it, equally spaced: a red hollow box, a green circle, a blue triangle, and a yellow four-pointed star.

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>

4.8.14.2 Processing model

If an img element has a usemap attribute specified, user agents must process it as follows:

Parse the attribute's value using the rules for parsing a hash-name reference to a map element, with the element as the context node. This will return either an element (the map) or null.
If that returned null, then return. The image is not associated with an image map after all.
Otherwise, the user agent must collect all the area elements that are descendants of the map. Let areas be that list.

Having obtained the list of area elements that form the image map (the areas), interactive user agents must process the list in one of two ways.

If the user agent intends to show the text that the img element represents, then it must use the following steps:

Remove all the area elements in areas that have no href attribute.
Remove all the area elements in areas that have no alt attribute, or whose alt attribute's value is the empty string, if there is another area element in areas with the same value in the href attribute and with a non-empty alt attribute.
Each remaining area element in areas represents a hyperlink. Those hyperlinks should all be made available to the user in a manner associated with the text of the img.

In this context, user agents may represent area and img elements with no specified alt attributes, or whose alt attributes are the empty string or some other non-visible text, in an implementation-defined fashion intended to indicate the lack of suitable author-provided text.

If the user agent intends to show the image and allow interaction with the image to select hyperlinks, then the image must be associated with a set of layered shapes, taken from the area elements in areas, in reverse tree order (so the last specified area element in the map is the bottom-most shape, and the first element in the map, in tree order, is the top-most shape).

Each area element in areas must be processed as follows to obtain a shape to layer onto the image:

Find the state that the element's shape attribute represents.
Use the rules for parsing a list of floating-point numbers to parse the element's coords attribute, if it is present, and let the coords list be the result. If the attribute is absent, let the coords list be the empty list.
If the number of items in the coords list is less than the minimum number given for the area element's current state, as per the following table, then the shape is empty; return.

State Minimum number of items
Circle state 3
Default state 0
Polygon state 6
Rectangle state 4
Check for excess items in the coords list as per the entry in the following list corresponding to the shape attribute's state:

Circle state
Drop any items in the list beyond the third.
Default state
Drop all items in the list.
Polygon state
Drop the last item if there's an odd number of items.
Rectangle state
Drop any items in the list beyond the fourth.
If the shape attribute represents the rectangle state, and the first number in the list is numerically greater than the third number in the list, then swap those two numbers around.
If the shape attribute represents the rectangle state, and the second number in the list is numerically greater than the fourth number in the list, then swap those two numbers around.
If the shape attribute represents the circle state, and the third number in the list is less than or equal to zero, then the shape is empty; return.
Now, the shape represented by the element is the one described for the entry in the list below corresponding to the state of the shape attribute:

Circle state

Let x be the first number in coords, y be the second number, and r be the third number.

The shape is a circle whose center is x CSS pixels from the left edge of the image and y CSS pixels from the top edge of the image, and whose radius is r CSS pixels.

Default state

The shape is a rectangle that exactly covers the entire image.

Polygon state

Let x_i be the (2i)th entry in coords, and y_i be the (2i+1)th entry in coords (the first entry in coords being the one with index 0).

Let the coordinates be (x_i, y_i), interpreted in CSS pixels measured from the top left of the image, for all integer values of i from 0 to (N/2)-1, where N is the number of items in coords.

The shape is a polygon whose vertices are given by the coordinates, and whose interior is established using the even-odd rule. [GRAPHICS]

Rectangle state

Let x₁ be the first number in coords, y₁ be the second number, x₂ be the third number, and y₂ be the fourth number.

The shape is a rectangle whose top-left corner is given by the coordinate (x₁, y₁) and whose bottom right corner is given by the coordinate (x₂, y₂), those coordinates being interpreted as CSS pixels from the top left corner of the image.

For historical reasons, the coordinates must be interpreted relative to the displayed image after any stretching caused by the CSS 'width' and 'height' properties (or, for non-CSS browsers, the image element's width and height attributes — CSS browsers map those attributes to the aforementioned CSS properties).

Browser zoom features and transforms applied using CSS or SVG do not affect the coordinates.

State	Minimum number of items
Circle state	3
Default state	0
Polygon state	6
Rectangle state	4

Pointing device interaction with an image associated with a set of layered shapes per the above algorithm must result in the relevant user interaction events being first fired to the top-most shape covering the point that the pointing device indicated, if any, or to the image element itself, if there is no shape covering that point. User agents may also allow individual area elements representing hyperlinks to be selected and activated (e.g. using a keyboard).

Because a map element (and its area elements) can be associated with multiple img elements, it is possible for an area element to correspond to multiple focusable areas of the document.

Image maps are live; if the DOM is mutated, then the user agent must act as if it had rerun the algorithms for image maps.

百度

4.8.12 The map element

4.8.13 The area element

4.8.14 Image maps

4.8.14.1 Authoring

4.8.14.2 Processing model

4.8.12 The `map` element

4.8.13 The `area` element