Try this one
<script type="text/javascript">
function isKeyPressed(event){
if (event.shiftKey==1){
alert("The shift key was pressed!")
}else{
alert("The shift key was NOT pressed!")
}
}
</script>
or
<script type="text/javascript">
function detectspecialkeys(e){
var evtobj=window.event? event : e
if (evtobj.shiftKey)
alert("you pressed the 'Shift' keys")
}
document.onkeypress=detectspecialkeys
</script>