function PopupScreenCentre(url,name,width,height,scrollbars)
	{
	 
		return PopupScreenCentreEx(url,name,width,height,scrollbars, 1, 0)
	 
	}

	function PopupScreenCentreEx(url,name,width,height,scrollbars, allowresize, showmenu)
	{
	var titleBarHeight, windowBorderWidth
		titleBarHeight = 24
		windowBorderWidth = 4
	
		var screenWidth, screenHeight
		screenWidth = 800
		screenHeight = 600
	 	if (window.screen) {
			if (window.screen.availWidth) {
				// ok browser has the appropriate properties we need to centre it
				screenWidth = window.screen.availWidth
				screenHeight = window.screen.availHeight
			}
		}
	
		// allow height to auto-shrink to fit screen
		if (height > screenHeight) {
			height = screenHeight - titleBarHeight - windowBorderWidth
			scrollbars = 1
		}
	
		var windowWidth = windowBorderWidth + width + windowBorderWidth
		var windowHeight = titleBarHeight + height + windowBorderWidth
	
		var left = (screenWidth - windowWidth) / 2
		var top = (screenHeight - windowHeight) / 2
	  	var win = window.open(url,name,'left='+left+',top='+top+',screenX='+left+',screenY='+top+',width='+width+',height='+height+',scrollbars='+scrollbars+',resizable='+allowresize+',toolbar=0,titlebar=0,location=0,directories=0,status=0,menubar='+showmenu+',copyhistory=0')
		if (window.focus) win.focus()
		
	}