var ns4 = (document.layers); 
var ie4 = (document.all &&!document.getElementById); 
var ie5 = (document.all && document.getElementById); 
var ns6 = (!document.all && document.getElementById); 



function popUp(id,dispattop) { 
	// Netscape 4 
	if(ns4){ 
		document.layers[id].visibility = "show"; 
	} 
	// Explorer 4 
	else if(ie4) { 
		document.all[id].style.visibility = "visible"; 
	} 
	// W3C - Explorer 5+ and Mozilla
	else if(ie5 || ns6) { 
		document.getElementById(id).style.visibility = "visible"; 
	}
	if (dispattop) {
	    document.getElementById(id).style.left = 50 
	    document.getElementById(id).style.top = 120
	}
	else {
		if (ie5) {
		    document.getElementById(id).style.left = window.event.clientX + document.body.scrollLeft 
	    	document.getElementById(id).style.top = window.event.clientY + document.body.scrollTop 
		} 
	}
} 

function popDown(id) { 
	// Netscape 4 
	if(ns4) { 
	document.layers[id].visibility = "hide"; 
	} 
	// Explorer 4 
	else if(ie4) { 
	document.all[id].style.visibility = "hidden"; 
	} 
	// W3C - Explorer 5+ and Netscape 6+ 
	else if(ie5 || ns6) { 
	document.getElementById(id).style.visibility = "hidden"; 
	} 
} 

function checkNum() {
	if (document.product.quantity.value.indexOf(".") != "-1" || isNaN(document.product.quantity.value)) {
		alert("You need to choose a number of items of this product - " + document.product.quantity.value + " is not a number!")
		return false
	}
	else {
		return true
	}
}

/////////////////////////////////// 
function clickIE() {if (document.all) {(message);return false;}} 
function clickNS(e) {if 
(document.layers||(document.getElementById&&!document.all)) { 
if (e.which==2||e.which==3) {(message);return false;}}} 
if (document.layers) 
{document.captureEvents(Event.MOUSEDOWN);document.onmousedown=clickNS;} 
else{document.onmouseup=clickNS;document.oncontextmenu=clickIE;} 
document.oncontextmenu=new Function("return false")