The onKeyUp event handler is fired when a key is released within the text area.
<html>
<head>
<script language="JavaScript1.2">
<!-- function showDialog(){
alert("A key was released");
}
-->
</script>
</head>
<body>
<form name="myForm">
<textarea name="myTextArea" rows=2 cols=50 onKeyUp='showDialog()'>
Here is some text in my text area.
</textarea>
</form>
</body>
</html>