<!DOCTYPE html>
<style type="text/css">
div[foo1^=""] { background-color: red; }
div[foo2$=""] { background-color: red; }
div[foo3*=""] { background-color: red; }
</style>
<div foo1="">[^=] attribute selector looking for empty string in empty attribute (the text should not have red background)</div>
<div foo2="">[$=] attribute selector looking for empty string in empty attribute (the text should not have red background)</div>
<div foo3="">[*=] attribute selector looking for empty string in empty attribute (the text should not have red background)</div>