Restrict input to alphanumeric and uppercase

<!--
Restrict input to alphanumeric and uppercase :
-->
<input type="text" onkeydown="f(this)" onkeyup="f(this)"
onblur="f(this)" onclick="f(this)" />
<!--
Javascript Code :
-->
<script language="javascript">
function f(o) {
o.value = o.value.toUpperCase().replace(/([^0-9A-Z])/g,"");
}
</script>