/**
 * lihang
 *
 * (1)  nav
 * (2)radom header 
 */
/*------radom header-------------------------------------------------------------------*/
var Folder = "subpage/"; // change directors

var how_many_ads = 4;
var now = new Date();
var sec = now.getSeconds();
var ad = sec % how_many_ads;
var css = "";
ad +=1;

if (ad == 1) {css = "header1.css";}
if (ad == 2) {css = "header2.css";}
if (ad == 3) {css = "header3.css";}
if (ad == 4) {css = "header4.css";}

self.headerstyle.href = Folder + css

/*------listmenu-------------------------------------------------------------------*/
function jumpmenu(formName, popupName, target) {
    var popup = document[formName].elements[popupName];
    if (popup.options[popup.selectedIndex].value != "") {
        window.open(popup.options[popup.selectedIndex].value, target);
        popup.selectedIndex=0;
    }
}