var message="";
function clickIE() {
	if (document.all) {(message);return false;}
}
function clickNS(e) {
	if(document.layers||(document.getElementById&&!document.all)) {
		if (e.which==2||e.which==3) {(message);return false;}
	}
}
if (document.layers) {
	document.captureEvents(Event.MOUSEDOWN);
	document.onmousedown=clickNS;
}else{
	document.onmouseup=clickNS;
	document.oncontextmenu=clickIE;
}



function disableCtrlKeyCombination(E){
	//list all CTRL + key combinations you want to disable
	var forbiddenKeys = new Array("a", "n", "c", "x", "v", "j");
	var key;
	var isCtrl;
	
	if(window.event)
	{
	        key = window.event.keyCode;     //IE
	        if(window.event.ctrlKey)
	                isCtrl = true;
	        else
	                isCtrl = false;
	}
	else
	{
	        key = e.which;     //firefox
	        if(e.ctrlKey)
	                isCtrl = true;
	        else
	                isCtrl = false;
	}
	
	//if ctrl is pressed check if other key is in forbidenKeys array
	if(isCtrl)
	{
	        for(i=0; i<forbiddenkeys .length; i++)
	        {
	                //case-insensitive comparation
	                if(forbiddenKeys[i].toLowerCase() == String.fromCharCode(key).toLowerCase())
	                {
	                        alert("Key combination CTRL + "
	                                +String.fromCharCode(key)
	                                +" has been disabled.");
	                        return false;
	                }
	        }
	}
	return true;
}


document.oncontextmenu="return false";
document.ondragstart = "return false";
document.onselectstart = "return false";
document.onkypressdown = "disableCtrlKeyCombination(event)";
document.onkypressdown = "disableCtrlKeyCombination(event)";