var queryString = window.location.href.substring((window.location.href.indexOf('?') + 1));
var array1 = queryString.split('&'); 
for(var i = 0; i < array1.length; i++)
 {
 var tempArray = array1[i].split('=');  
 var param = tempArray[0];
 eval(tempArray[0] + " = \"" + tempArray[1] + "\"");
 switch (tempArray[1])
  {
   case "179579": 
       createPixelFrame(tempArray[1]);
   break;
 default : ("");
  }
 }

function createPixelFrame(adid) { 
   iframe = document.createElement("IFRAME"); 
   iframe.setAttribute("src", "http://www.riverbelle.co.uk/tracking/pixel.asp?a=" + adid); 
   iframe.style.width = 1+"px"; 
   iframe.style.height = 1+"px"; 
   document.body.appendChild(iframe); 
}