var viewerdiv = 'not set';
	

	
	function openviewer(div) {
	document.getElementById(div).style.visibility = 'visible';
	 viewerdiv = div;
	 
	
	
	}
	function closeviewer(div) {
	document.getElementById(div).style.visibility = 'hidden';
	}
		document.onkeydown = checkKeycode
function checkKeycode(e) {
var keycode;
if (window.event) keycode = window.event.keyCode;
else if (e) keycode = e.which;
if(keycode != 27) 
alert();
else
closeviewer(viewerdiv);
}