function openCenterPopup( file, width, height ) {
	x = parseInt( screen.availWidth / 2 ) - ( parseInt ( width / 2 ) );	
	y = parseInt( screen.availHeight / 2 ) - ( parseInt ( height / 2 ) );	

	features_of_window = "\"" + "menubar=false," + "width=" + width + "," + "height=" + height + "," + "left=" + x + "," + "top=" + y + ","	+ "screenX=" + x + "," + "scrollbars=no," + "screenY=" + y + "\"";
	
	window.open( file, "popup", features_of_window );
}