var left = Math.round(screen.availWidth/2)
var top = Math.round(screen.availHeight/2)

var popupwindow = 0
var windowName = "main"

function popUp(width, height, target){
	popupwindow++
	window.open(target,windowName+popupwindow,"width="+width+",height="+height+",top="+(top - Math.round(height/2))+",left="+(left - Math.round(width/2))+",scrollbars=yes,resizable=no,menubar=no,toolbar=no")
}