<body>
<input type="text" name="aaa" onkeydown="return shiftCtrlAlt()">
</body>
<script language="javascript">
function shiftCtrlAlt()
{
if(event.ctrlKey == 1) return false;
if(event.altKey == 1) return false;
if(event.shiftKey == 1) return false;
}
</script>
<input type="text" name="aaa" onkeydown="return shiftCtrlAlt()">
</body>
<script language="javascript">
function shiftCtrlAlt()
{
if(event.ctrlKey == 1) return false;
if(event.altKey == 1) return false;
if(event.shiftKey == 1) return false;
}
</script>