The onBlur property notifies you when the focus is removed from a radio button.
<html>
<head>
<title> Example of the Radio onBlur event handler</title>
</head>
<body>
<script language="JavaScript">
<!--
function showChange(){
document.form1.text1.value = "Focus removed from Radio Button";
}
-->
</script>
<form name="form1">
Click the radio button first, then click in the text area.
<br><br>
<input type="radio" name=button1 onBlur='showChange()'>Box 1
<br>
Click the text box
<input type="text" name="text1" size=40>
<br>
</form>
</body>
</html>