Inline style to act as :hover in CSS

I know that embedding CSS styles directly into the HTML tags they affect defeats much of the purpose of CSS, but sometimes it's useful for debugging purposes, as in:

<p style="font-size: 24px">asdf</p>

What's the syntax for embedding a rule like:

a:hover {text-decoration: underline;}

into the style attribute of an A tag? It's obviously not this...

<a href="foo" style="text-decoration: underline">bar</a>

...since that would apply all the time, as opposed to just during hover.

I'm afraid it can't be done, the pseudo-class selectors can't be set in-line, you'll have to do it on the page or on a stylesheet.

I should mention that technically you should be able to do it according to the CSS spec, but most browsers don't support it

Edit: I just did a quick test with this:

<a href="test.html" style="{color: blue; background: white} 
			:visited {color: green}
			:hover {background: yellow}
			:visited:hover {color: purple}">Test</a>

And it doesn't work in IE7, IE8 beta 2, Firefox or Chrome. Can anyone else test in any other browsers?

If you are only debugging, you might use javascript to modify the css:

<a onmouseover="this.style.textDecoration='underline';" 
    onmouseout="this.style.textDecoration='none';">bar</a>

A simple solution:

<a href="#" onmouseover="this.style.color='orange';" onmouseout="this.style.color='';">My Link</a>

Or

<script>
 /** Change the style **/
 function overStyle(object){
    object.style.color = 'orange';
    // Change some other properties ...
 }

 /** Restores the style **/
 function outStyle(object){
    object.style.color = 'orange';
    // Restore the rest ...
 }
</script>

<a href="#" onmouseover="overStyle(this)" onmouseout="outStyle(this)">My Link</a>

If it's for debugging, just add a css class for hovering (since elements can have more than one class):

a.hovertest:hover
{
text-decoration:underline;
}

<a href="http://example.com" class="foo bar hovertest">blah</a>

I put together a quick solution for anyone wanting to create hover popups without CSS using the onmouseover and onmouseout behaviors.

http://jsfiddle.net/Lk9w1mkv/

<div style="position:relative;width:100px;background:#ddffdd;overflow:hidden;" onmouseover="this.style.overflow='';" onmouseout="this.style.overflow='hidden';">first hover<div style="width:100px;position:absolute;top:5px;left:110px;background:white;border:1px solid gray;">stuff inside</div></div>

If that <p> tag is created from JavaScript, then you do have another option: use JSS to programmatically insert stylesheets into the document head. It does support '&:hover'. https://cssinjs.org/

I don't think jQuery supports the pseudo-selectors either, but it does provide a quick way to add events to one, many, or all of your similar controls and tags on a single page.

Best of all, you can chain the event binds and do it all in one line of script if you want. Much easier than manually editing all of the HTML to turn them on or off. Then again, since you can do the same in CSS I don't know that it buys you anything (other than learning jQuery).