var imgArray = new Array(); 
   number = 0;  
   // imageArray 
   imgArray[number++] = "images/random/1.jpg" 
   imgArray[number++] = "images/random/2.jpg"
   imgArray[number++] = "images/random/3.jpg"   
   imgArray[number++] = "images/random/4.jpg" 
   imgArray[number++] = "images/random/5.jpg"
   imgArray[number++] = "images/random/6.jpg"
 increment = Math.floor(Math.random() * number);
 document.getElementById("imbBkg").background = imgArray[increment];