var xOffset = -50;
 var yOffset = -140;
 var oCurrentVisibleLayer;

function showHideLayer(id, e){
    if(e) {

		if (navigator.appName.indexOf("Microsoft")!=-1) {
			clientHeight = document.body.clientHeight / 2 - 100;
			clientWidth = document.body.clientWidth / 2 - 100;
		}else{
			clientHeight = window.innerHeight;
			clientWidth = window.innerWidth;
		}

		side_padding = (clientWidth - 1200) / 2;
		if (side_padding < 0){
			side_padding = 0;
		}
		
		element = document.getElementById(id); 
		if (element.style.visibility != 'visible'){
			var newX = e.clientX - document.body.scrollLeft - side_padding;
			var newY = e.clientY - document.body.scrollTop - 140;
			
			element.style.top = newY + 'px';
			element.style.left = newX + 'px';

			element.style.visibility = 'visible';
			element.style.display = 'block';
		}else{
			element.style.visibility = 'hidden';
			element.style.display = 'none';
		}

		return true;
	}else{
		return false;
	}
}

function checkEnter(e){ //e is event object passed from function invocation
	var characterCode; // literal character code will be stored in this variable

	if(e && e.which){ //if which property of event object is supported (NN4)
		e = e;
		characterCode = e.which; //character code is contained in NN4's which property
	}else{
		e = event;
		characterCode = e.keyCode; //character code is contained in IE's keyCode property
	}

	if(characterCode == 13){
		return true;
	}else{
		return false;
	}
}