RegEx matching in Javascript?

[Jaxel]

This works great... But I am having one issue incorporating this with Ajax...

This is the text field to be edited...

<div class="editUse"><img src="ranking/usage/amy.gif"></div>

When I click on the div, the following Javascript process runs:

function editBox_use(actual) {
	if(!changing) {
		actual.innerHTML = fetch_usage(actual.innerHTML).join(',');
		actual.innerHTML = "<input id=\""+ actual.id +"_field\" type=\"text\" value=\"" + actual.innerHTML + "\" onkeypress=\"return fieldEnter(this,event,'" + actual.id + "')\" onblur=\"return fieldBlur(this,'" + actual.id + "');\" style=\"width:50px; text-align:center; font-size:12px; \" />";
		changing = true;
	}
	actual.firstChild.focus();
}

function fetch_usage(code) {
	matches = new Array();
	while (code.match(/(<img src="\w+\/usage\/(\w+?)\.gif">)/i)) {
		matches.push(RegExp.$2);
		code = code.replace(RegExp.$1, '', code);
	}
	return matches;
}

This works great, and the text box correctly fills out with "amy". After I edit the box, the following PHP script is run:
($input is the new value where "amy" once was, lets say for now it is "cas")

function update_score($input)
{
	global $thumbdir;

	$input = str_replace(' ','',$input);
	$input = strtolower($input);

	$uses = explode(',',$input);

	foreach ($uses as $use)
	{
		$usage .= '<img src="'.$thumbdir.'/usage/'.$use.'.gif">';
	}

	echo $usage;
}

Running this script properly and returns the image for "cas" right on the page:

<div class="editUse"><img src="ranking/usage/cas.gif"></div>

However, now a new issue comes up... THEORETICALLY, if I click on the div AGAIN (without refresshing the page), it should return the text box filled out with the word "cas". It doesn't instead it gives me a blank text box. If I refresh the page, it works fine, but if I don't (which is the purpose of AJAX), the regex script fails.

Is there something wrong with the way the new HTML is echoed out that makes it fail the matching?