document.onkeydown = function() {
		var e = event || window.event;
		var keyASCII = parseInt(e.keyCode, 10);
		var src = e.srcElement;
		var tag = src.tagName.toUpperCase();
		if(keyASCII == 13) 
		{
			return false;
		}
		if(keyASCII == 8) 
		{
			if(src.readOnly || src.disabled || (tag != "INPUT" && tag != "TEXTAREA")) 
			{
				return false;
			}
			if(src.type) 
			{
				var type = ("" + src.type).toUpperCase();
				return type != "CHECKBOX" && type != "RADIO" && type != "BUTTON";
			}
		}
		return true;
		}