I found somewhere that I can use backslash in CSS id# as an exception on some pages that have two id names in same selector. And it works, but I can't find any reference and what version of CSS can use it. Any explanation?
CSS:
#content\ shopWide .someclass {
width: 37px;
background: khaki;
}
HTML:
<div id="content shopWide"><div class="someclass">blah</div>