document.oncontextmenu=showNoContextMenu;
document.onkeydown=verifyKeyInput;

function showNoContextMenu()
{
	return false;
}

function verifyKeyInput()
{
	var keyDisabled;
	var objActive;
	
	objActive=document.activeElement;
	keyDisabled=false;
	
	if ((window.event.ctrlKey) && (window.event.keyCode == 78))
		keyDisabled=keyDisabled || true;
	
	if (window.event.keyCode == 8) 
		if ( ((objActive.tagName == 'INPUT') && ((objActive.type == 'text') || (objActive.type == 'password'))) || (objActive.tagName == 'TEXTAREA') ) 
			keyDisabled=keyDisabled || false;
		else
			keyDisabled=keyDisabled || true;

	if ((window.event.altKey) && (window.event.keyCode == 37))
		keyDisabled=keyDisabled || true;
	
	if ((window.event.altKey) && (window.event.keyCode == 39))
		keyDisabled=keyDisabled || true;
	
	if (window.event.keyCode == 122)
		keyDisabled=keyDisabled || true;
	
	return !(keyDisabled);
}