function RunMainRandom()
{

var topbanner=new Array()

topbanner[0]='<div class="index_image1">'

topbanner[1]='<div class="index_image2">'

topbanner[2]='<div class="index_image3">'

topbanner[3]='<div class="index_image4">'

var whichtop=Math.floor(Math.random()*(topbanner.length))
document.write(topbanner[whichtop])
}