I discovered this:
I've been checking lots of form fields for a blank value (eg. they contain nothing, or just whitespace) lately, and I wanted to emulate Rails' String#blank? to check this in jQuery.
I had been doing something like this:
if($.trim($(this).val()) == '') ...
But that's so ugly I felt there must be a better way. Of course, there is:
Simple, clear, and jQuery-ish.