function randomAdv() {
   m = 0, x = 0, y = 0;
   ad  = new Array();
   adv = new Array();
   hit = new Array();
   id = new Array(); 
   adsid = 0;
hit[0] = 100;id[0] = 3;adv[0] = '<a href="/Advertising/index.aspx?id=3&mode=1" target="_blank"><img src="/_images/users/advertising/20100806095156.jpg" /></a>';

   for(i=0; i<=hit.length - 1; i++) {
     m += hit[i];
   }
   n = Math.floor(Math.random() * m);
   n++;
   for(i=0; i<=hit.length - 1; i++) {
     x = y;
     y += hit[i];
     if(x<n && n<=y){ ad = adv[i];adsid = id[i];}
   }
   document.write(ad);
   $.ajaxSetup({ cache: false });
   $.get("/Advertising/index.aspx",{id:adsid});
 }