a = 5 // a=numbers of banners
var slump = Math.random();
var talet = Math.round(slump * (a-1))+1;
function create() {
this.under = ''
}
b = new Array()
for(var i=1; i<=a; i++) { b[i] = new create() }
b[1].under = ' [广告] 菩提经舍欢迎您！'
b[2].under = ' [广告] 菩提经舍期待您的加入！'
b[3].under = ' [广告] 阿弥陀佛！'
b[4].under = ' [广告] 菩提经舍有您要结缘的书籍吗？'
b[5].under = ' [广告] 本社区广告位招租，需要者请来信联系'
var visa = "";
document.write(b[talet].under+'');
//阿弥陀佛