[jQuery] continuously search for elements in a document

[jQuery] continuously search for elements in a document


(Using jQuery w/ ASP.NET 2.0)
I have a few error prompts that are in hidden spans inside <li>'s. I
need to hide the LI's when the error prompt is hidden.
Example:
$(document).ready(function() {
//hide empty error spans
$('ul.errors li span').each(function(i){
if($(this).css("display") == "none") {
$(this).parent().hide();
};
});
});
This works, but only on page load. These error prompts display as
needed on onBlur (via .NET default methods).
How can I continuously scan the document for these error prompts and
show/hide the parent LI's when the prompts show/hide?
Thanks,
-rich