Automatic random selection codes javascript

Automatic random selection javascript code is not explained specifically what purpose.

<script language="javascript">
function dogo(){
var urls = new Array();
urls[0]="http://www.baidu.com";
urls[1]="http://www.52pojie.cn";
urls[2]="http://www.qq.com";
urls[3]="http://www.360.com";
urls[4]="http://www.sogou.com";
n = Math.floor(Math.random()*5);
location.href= urls[n];
}
</script>