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<html><head><script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script><script>$(document).ready(function(){ $(":radio").wrap("<span style='background-color:red'>");});</script></head><body><form action=""> Name: <input type="text" name="user"><br> Male:<input type="radio" name="sex" value="m"><br> Female<input type="radio" name="sex" value="f"><br> <input type="submit"></form><p>Note: We use jQuerys .wrap method to highlight the selected elements, because Firefox does not support background color on radiobuttons.</p></body></html>