JS禁止右击菜单

function key(){
if(event.shiftKey){
window.close();}
//禁止Shift
if(event.altKey){
window.close();}
//禁止Alt
if(event.ctrlKey){
window.close();}
//禁止Ctrl
return false;}
document.onkeydown=key;



function nocontextmenu(){
	//alert("a");
	try{
	   event.cancelBubble = true
	   event.returnValue = false;
	}catch(e){

	}
	return false;
}

function norightclick(){
  if (event.button == 2 || event.button == 3){
	//alert("a");
	try{
	   event.cancelBubble = true
	   event.returnValue = false;
	}catch(e){

	}	
	return false;
   }
}


document.oncontextmenu = nocontextmenu;  // for IE5+
document.onmousedown = norightclick;  // for all others

document.onselectstart = function(){
	return false;
}
document.ondragstart =  function(){
	return false;
}