How to redirect to one out of given set of sites?

I created a userscript to redirect to one out of the specified multiple sites:

// ==UserScript==
// @id             fvhfy464
// @name           [udit]redirector to yahoo or google
// @version        1.0
// @namespace      
// @author         
// @description    
// @include        http://yahoo.com
// @include        http://google.com
// @include        http://bing.com
// @run-at         document-end
// ==/UserScript==

setTimeout(function() {
    window.location.href("http://yahoo.com","http://google.com","http://bing.com")
}, 4000);

But it doesn't work.

(From comments:)
I want to open multiple sites in a single tab, one after another, in a random way with a time interval of 4 seconds. It's like a screensaver of sites.

It can go forever. To stop, I just have to close the tab. And, I'll only set those sites in the @include which I want this script to work on. It's like a screensaver of photos etc.

Solution

Put the list of sites, you want to display, into an array. Then you can key off the current page and either go to the next one in order, or pick a random next one.

For example, here is an ordered slide-show:

// ==UserScript==
// @name        Multipage, MultiSite slideshow of sorts
// @match       http://*.breaktaker.com/*
// @match       http://*.imageshack.us/*
// @match       http://static.tumblr.com/*
// @match       http://withfriendship.com/images/*
// ==/UserScript==

var urlsToLoad  = [
    'http://www.breaktaker.com/albums/pictures/animals/BigCat.jpg'
    , 'http://img375.imageshack.us/img375/8105/bigcats34ye4.jpg'
    , 'http://withfriendship.com/images/g/33769/1.jpg'
    , 'http://static.tumblr.com/yd0wcto/LXQlx109d/bigcats.jpg'
];

setTimeout (GotoNextURL, 4000);

function GotoNextURL () {
    var numUrls     = urlsToLoad.length;
    var urlIdx      = urlsToLoad.indexOf (location.href);
    urlIdx++;
    if (urlIdx >= numUrls)
        urlIdx = 0;

    location.href   = urlsToLoad[urlIdx];
}

Here's the same sites served up randomly:

// ==UserScript==
// @name        Multipage, MultiSite slideshow of sorts
// @match       http://*.breaktaker.com/*
// @match       http://*.imageshack.us/*
// @match       http://static.tumblr.com/*
// @match       http://withfriendship.com/images/*
// ==/UserScript==

var urlsToLoad  = [
    'http://www.breaktaker.com/albums/pictures/animals/BigCat.jpg'
    , 'http://img375.imageshack.us/img375/8105/bigcats34ye4.jpg'
    , 'http://withfriendship.com/images/g/33769/1.jpg'
    , 'http://static.tumblr.com/yd0wcto/LXQlx109d/bigcats.jpg'
];

setTimeout (GotoRandomURL, 4000);

function GotoRandomURL () {
    var numUrls     = urlsToLoad.length;
    var urlIdx      = urlsToLoad.indexOf (location.href);
    if (urlIdx >= 0) {
        urlsToLoad.splice (urlIdx, 1);
        numUrls--;
    }

    urlIdx          = Math.floor (Math.random () * numUrls);
    location.href   = urlsToLoad[urlIdx];
}