// verhinderung der strg taste (shortcuts)
document.onkeydown = document.onkeypress = Tastendruck;

function Tastendruck(e) 
{
	
	if (!e)
	{
		e = window.event;
	}

	if (!e)
	{
		return true;
	}

	var keyCode = e.keyCode ? e.keyCode : (e.charCode ? e.charCode : e.which);
	if (e.ctrlKey)
	{
		if(keyCode == 67 || keyCode == 65 || keyCode == 97 || keyCode == 99)
		{
		 return false;
		}
	}
}