var popWin = null    // use this when referring to pop-up window
var winCount = 0
var winName = "popWin"

function openPopWin(winURL, winWidth, winHeight, winFeatures, winLeft, winTop){

	if (screen) {
		d_winLeft = (screen.availWidth/2)-(winWidth/2);
		d_winTop  = (screen.availHeight/2)-(winHeight/2);
	}

	winName = "popWin" + winCount++ //unique name for each pop-up window
	closePopWin()           // close any previously opened pop-up window
	if (openPopWin.arguments.length >= 4)  // any additional features?
	winFeatures = "," + winFeatures
	else
	winFeatures = ""
	if (openPopWin.arguments.length == 6)  // location specified
	winFeatures += getLocation(winWidth, winHeight, winLeft, winTop)
	else
	popWin = window.open(winURL, winName, "width=" + winWidth
	+ ",height=" + winHeight +",left="+d_winLeft+", top="+d_winTop+",scrollbars=yes")
}
function closePopWin(){    // close pop-up window if it is open
	if (navigator.appName != "Microsoft Internet Explorer"
	|| parseInt(navigator.appVersion) >=4) //do not close if early IE
	if(popWin != null) if(!popWin.closed) popWin.close()
}
function getLocation(winWidth, winHeight, winLeft, winTop){
	return ""
}