HTML Guide
Empty target on an <area> element is invalid; it must be a named browsing context (at least one character) or a valid keyword like _self, _blank, _parent, or _top.
The target attribute on hyperlinked elements such as <a> and <area> controls where to open the linked resource. It accepts either a named browsing context (e.g., target="mapFrame") or one of the standard keywords: _self (default, same frame/tab), _blank (new tab/window), _parent, or _top. An empty string "" is not allowed and causes validation errors. Choose the appropriate keyword or remove target if default behavior is desired. If you need to direct links to a specific frame or iframe, use a non-empty name and ensure the frame has a matching name attribute.
HTML Examples
Invalid example (reproduces the error)
<img src="plan.png" usemap="#site-map" alt="Site map">
<map name="site-map">
<area shape="rect" coords="10,10,100,60" href="/about" alt="About" target="">
</map>Fixed examples
<!-- Use a valid keyword -->
<img src="plan.png" usemap="#site-map" alt="Site map">
<map name="site-map">
<area shape="rect" coords="10,10,100,60" href="/about" alt="About" target="_self">
</map><!-- Or remove target to use default behavior -->
<img src="plan.png" usemap="#site-map" alt="Site map">
<map name="site-map">
<area shape="rect" coords="10,10,100,60" href="/about" alt="About">
</map><!-- Or target a named iframe -->
<iframe name="mapFrame" src="about:blank" title="Content frame"></iframe>
<img src="plan.png" usemap="#site-map" alt="Site map">
<map name="site-map">
<area shape="rect" coords="10,10,100,60" href="/about" alt="About" target="mapFrame">
</map>Learn more:
Related W3C validator issues
The target attribute on <a> elements can’t be blank.
This attribute defines the browsing context for links, that is, where should the linked documents be opened. This was used extensively on the now deprecated <frame> element, so you could give the name of the frame to open the document in, but is now more used to force links to open in a separate tab or window using target="_blank". Another option is using a name, so the new browsing context can be referred to on subsequent clicks on links with the same target.
For example, this will force the links to open on a new tab:
<a href="https://example.com" target="_blank">will open a blank tab</a>“polygon” is not a valid value for the shape attribute on an area element; the correct value is poly.
The area element defines clickable regions inside an image map via usemap. Its shape attribute only accepts rect, circle, poly, or default per the HTML standard. When using poly, list the coords as comma-separated x,y pairs in order around the polygon. Coordinate values are CSS pixels relative to the image’s intrinsic dimensions. Always include an alt for accessibility and an href to make the region interactive. If the region is a circle or rectangle, use circle or rect with the appropriate coordinate syntax.
HTML Examples
Example showing the issue
<!doctype html>
<html lang="en">
<head>
<title>Image Map - Invalid</title>
</head>
<body>
<img src="plan.png" usemap="#map1" alt="Floor plan">
<map name="map1">
<area shape="polygon" coords="10,10,80,10,80,60,10,60" href="room-a.html" alt="Room A">
</map>
</body>
</html>Corrected example
<!doctype html>
<html lang="en">
<head>
<title>Image Map - Valid</title>
</head>
<body>
<img src="plan.png" usemap="#map1" alt="Floor plan">
<map name="map1">
<area shape="poly" coords="10,10,80,10,80,60,10,60" href="room-a.html" alt="Room A">
</map>
</body>
</html>An href attribute with the value http:// is not a valid URL because the host section is missing.
The href attribute in the area element must contain a valid URL. A URL requires a scheme (http or https), followed by ://, and then a valid host (such as example.com). The value http:// lacks a host, making it invalid according to URL standards and resulting in a validation error. If you don’t want the area to navigate anywhere, you can use href="#" for a placeholder or omit the href attribute entirely. To link to an actual location, provide the complete URL, including the host.
Invalid example:
<map name="myMap">
<area shape="rect" coords="30,23,183,191" href="http://" alt="" >
</map>Valid example with a real host:
<map name="myMap">
<area shape="rect" coords="30,23,183,191" href="http://example.com/" alt="" >
</map>Valid example with a placeholder, no navigation:
<map name="myMap">
<area shape="rect" coords="30,23,183,191" href="#" alt="" >
</map>Replace http:// with a full URL or a suitable placeholder as needed for your application.
The value used in the target property of an <a> element has been identified as a keyword because it starts with an underscore _, but it’s not a valid keyword.
Values starting with an underscore for the target property are used for reserved keywords like _blank, _self, _parent or _top.
The coordinates specified for an <area> element using the coords attribute are not in a valid format.
-
For a rectangle (shape="rect"), the format X1,Y1,X2,Y2 is expected, where the top-left corner is specified by X1, Y1 and the bottom-right corner is specified by X2, Y2, therefore X1 must be lower than X2, and Y1 must be lower than Y2 because the coordinates 0, 0 start at the top-left.
-
For a polygon (shape="poly"), the format X1,Y1,X2,Y2,...,Xn,Yn is expected to contain a list of coordinate pairs (at least 3, for a triangle).
-
For a circle (shape="circle"), the format X,Y,R is expected where X, Y represents the coordinates of the center of the circle (from the top-left corner), and R is the radius.
Links created with the <a> element no longer accept a shape attribute. In order to define image maps, use the <area> element instead.