var IE = (document.all ? true : false);
var NS4 = (document.layers ? true : false);
var ScreenX = screen.width;
var ScreenY = screen.height;
if(IE) {
     doc = "document";
     sty = "";
     htm = ".document"
} else if(NS4) {
     doc = "document.all";
     sty = ".style";
     htm = "";
}
function openCenter(url, name, feat, w, h){
        window.open(url, name, "width=" + w + ",height=" + h + ",left=" + ((ScreenX / 2) - (w / 2)) + ",top=" + ((ScreenY / 2) - (h / 2) - 20) + "," + feat);
}

function image_preview(id, w, h){
        w=640;
        h=480;
	window.open("image.php?id=" + id, name, "width=" + (w+10) + ",height=" + (h+100) + ",left=" + ((ScreenX / 2) - (w / 2)) + ",top=" + ((ScreenY / 2) - (h / 2) - 20) + "," + 'scrollbars=yes');
}