js截取相应的域名

var urlReg = /[a-zA-Z0-9][-a-zA-Z0-9]{0,62}(\.[a-zA-Z0-9][-a-zA-Z0-9]{0,62})+\.?/;  
var url=urlReg.exec("http://www.baidu.com/aaaa");  
console.log(url[0]);  

返回结果：www.baidu.com