Order of onmouseover events with image and imagemap

Posted on 2008-10-23
Medium Priority
Last Modified: 2012-05-05
So, this must be an order of operation thing.  In IE this works perfectly:

        <img id="img_123" src="img/skill1.png" class="skillImg"
             usemap="#skillMap" ismap="ismap"
             onmouseover="document.getElementById('tempsid').value=this.src;this.src='img/skill' + hoverSkill.valueOf + '.png';this.className='skillImg dim';"

<map id="skillMap" name="skillMap" style="boder:solid 1px red;">
    <area shape="rect" coords="0,0,12,12" title="In Training"
          onmouseover="swapImage(1);" />
    <area shape="rect" coords="13,0,24,12" title="Trained/Monitored"
          onmouseover="swapImage(2);" />
    <area shape="rect" coords="13,13,24,24" title="Qualified at Standard Rate"
          onmouseover="swapImage(3);" />
    <area shape="rect" coords="0,12,12,24" title="Trainer"
          onmouseover="swapImage(4);" />

<script language="JavaScript" type="text/javascript">

var hoverSkill = new Object();
hoverSkill.valueOf = 0;

function swapImage(val) {
    hoverSkill.valueOf = val;

In Firefox, the image map onmouseover event works fine, but the image mouseover event doesn't fire.

So, is that it.  IE will perform both the image and map mouseover events, while Firefox will only handle the map mouseover events?
Question by:Steve Krile
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LVL 82

Expert Comment

ID: 22790585
make sure you put:
<script language="JavaScript" type="text/javascript"> 
var hoverSkill = new Object();
hoverSkill.valueOf = 0; 

function swapImage(val) {
    hoverSkill.valueOf = val;
BEFORE the <map id="skillMap" name="skillMap" style="boder:solid 1px red;">...</map> 
Otherwiser hoverSkill will be out of scope

Open in new window

LVL 16

Author Comment

by:Steve Krile
ID: 22795190
I have.  The script is loaded at the top of the page in a script tag in the head like:

<script type="text/javascript" src="js/ManageEmployees_skills.js" type="text/javascript" language="javascript"></script>

LVL 16

Accepted Solution

Steve Krile earned 0 total points
ID: 22795529
Shadow's answer on this link seems to cover it.  There is a difference in the way IE and FireFox handle image maps, and there's no "good" way to overcome that difference.


Just some extra info.

XHTML 1.0 doctypes require an id attribute for the map element, but also allow the name attribute if it has the same value as the id attribute.

The usemap attribute for the img, input and object element is of type "URI"; meaning that when you do usemap="#somemap", the value is a resolved value of location.href + #somemap, which references an element in the document with a name or id of somemap. So if the page is http://somesite.com/test.html and you have usemap="#somemap", internally in the browser, the usemap value would be http://somesite.com/test.html#somemap .

With the XHTML 1.1 doctype, id is required for the map element, but the name attribute is not allowed. The usemap attribute for img, input and object is of type "idref"; meaning the value is just a reference to an id and when you do usemap="somemap", it just references an element with id="somemap". Because it's just an idref, # isn't allowed in the usemap attribute value.

As for browsers:

IE, Opera and Safari only support image maps the "uri" way regardless of doctype or mime type. Safari doesn't seem to support image maps for the input and object element at all. (at least 1.3).

Now Firefox goes by mime type. If you serve XHTML 1.0 or XHTML 1.1 as application/xhtml+xml, Firefox uses the idref way. If you serve XHTML 1.0 or XHTML 1.1 as text/html, Firefox uses the uri way. However, Firefox still plays nice and allows # when it's using the idref way.

(XHTML 1.1 is not to be served as text/html so you could say that Firefox is only in violation of xhtml 1.0. because the usemap type shouldn't change with the mime type. Firefox should follow the standard XHTML 1.0 doctypes regardless of the mime type. Serving as application/xhtml+xml means you can forget about IE)

If you serve XHTML 1.0 as text/html you really have no worries. If you serve it as application/xhtml+xml, you have to make sure both the name and id attributes are the same for the map element and use # so all application/xhtml+xml browsers are happy. Same thing goes for XHTML 1.1. Now at any time the validator complains (once you've done everything you are supposed to) you can always use a custom doctype or add attribute declarations to the doctype so the validator doesn't throw a fit. An example of this woud be for the XHTML 1.1 doctype, where you change the usemap type declaration to uri and add the name attribute to the map element.

As said above, Opera does't support XHTML 1.1 image maps, but there's a user javascript fix that makes them work while using fully compliant code with a non-modified XHTML 1.1 doctype served as application/xhtml.


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