function onKeyDown() {  
	// current pressed key  
	var pressedKey = String.fromCharCode(event.keyCode).toLowerCase();   
	if (event.ctrlKey && (pressedKey == "c" ||                         
	pressedKey == "v")) {    
		// disable key press porcessing    
		event.returnValue = false;  
	} 
} 
// onKeyDown