var image_names = ['elearn.gif'] ;
var link_addr = ['http://www.icivil.ir/store/aoutocad/cat/'] ;
var r = Math.floor(Math.random() *1);
document.write('<a target=_blank href="' +  link_addr[r] + '">' +  '<img width="170" height="285" border="0" src="http://icivil.ir/adimg/' + image_names[r] + '">') ;