/*
* Open a centered window
*/

function openCentered (url, w, h, winName, features) {
	if (!winName) winName = '';

	//	menubar, scrollbars, status, toolbar, directories, resizable, fullscreen

	if (!features) features = '';
	else features = ',' + features;

	var x = (screen.availWidth) ? Math.round((screen.availWidth - w) / 2) : 0;
	var y = (screen.availHeight) ? Math.round((screen.availHeight - h) / 2) : 0;

	features = 'left=' + x + ',top=' + y + ',width=' + w + ',height=' + h + features;
	return open(url, winName, features);
}