function randimg() {}  
var adImg = new Array() ;  
//-------------Database---------- 
adImg[0]= '<img src="images/main_index_FB.jpg">' 
adImg[1]= '<img src="images/main_index_BB.jpg">'
adImg[2]= '<img src="images/main_index_TR.jpg">'

var num=Math.floor(Math.random() * adImg.length) ;