var oImgs=new Array( 
 "img/Success-header-shunde1-CN-JPEG.jpg", 
 "img/Tomorrow-header-CN-JPEG.jpg"
 ); 
var n=oImgs.length-1; 
var currIndex=Math.round(Math.random() * n) 
document.write("<img src="+oImgs[currIndex]+">")