Q:

if class equals something then add attrib to another div

I am trying to write a function that will look for the class name "blocknew", and then add to the imgframe div's style attribute. Is this even possible?
Go from this:
<div class="block"><div class="imgframe" style="background:url(images/blah.jpg);"></div></div>

To this:
<div class="blocknew"><div class="imgframe" style="background:url(images/new.jpg), url(images/blah.jpg);"></div></div>

Function I have so far:
$(function () { $('.blocknew').children('.imgframe').attr("style", "background:url(images/new.png),"); });

A:

After much discussion, this could be what OP means
$('.block .imgframe').each(function(){
    $(this).css('background', 'url(images/new.jpg),' + $(this).css('background'));
});

