Disable copy paste from webpage

<!-- Disable Ctrl+U-->
	<script type='text/javascript'>
	var isCtrl = false;
	document.onkeyup=function(e)
	{
	if(e.which == 17)
	isCtrl=false;
	}
	document.onkeydown=function(e)
	{
	if(e.which == 17)
	isCtrl=true;
	if((e.which == 85) && (isCtrl == true))
	{
	return false;
	}
	else if((e.which==67) && (isCtrl == true))
	{
	alert("Sorry, You can not copy content from eshikhon.com");
	return false;
	}
	}
	var isNS = (navigator.appName == "Netscape") ? 1 : 0;
	if(navigator.appName == "Netscape") document.captureEvents(Event.MOUSEDOWN||Event.MOUSEUP);
	function mischandler(){
	return false;
	}
	function mousehandler(e){
	var myevent = (isNS) ? e : event;
	var eventbutton = (isNS) ? myevent.which : myevent.button;
	if((eventbutton==2)||(eventbutton==3)) return false;
	}
	document.oncontextmenu = mischandler;
	document.onmousedown = mousehandler;
	document.onmouseup = mousehandler;
	</script>
	<!-- END Disable Ctrl+U-->