var rutaimagen_left = new Array(
"left_01.jpg","left_02.jpg","left_03.jpg","left_04.jpg","left_05.jpg","left_06.jpg","left_07.jpg","left_08.jpg"
)
//var ran_number_left=Math.round(Math.random()*7);
var ran_number_left=ran_number;
imgselect_left = rutaimagen_left[ran_number_left];
//alert(imgelect);
document.getElementById('ad_left').innerHTML='<img src="images/'+imgselect_left+'"  border="0" alt="" />';