<!DOCTYPE html>
<html lang="zh-cn">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script>
function getHost(url) {
    var host = "null";
    if(typeof url == "undefined"|| null == url) {
        url = window.location.href;
    }
    var regex = /^\w+\:\/\/([^\/]*).*/;
    var match = url.match(regex);
    if(typeof match != "undefined" && null != match) {
        host = match[1];
    }
    return host;
}
document.write(getHost("http://onestopweb.iteye.com/blog/2327754"));
</script>	
</body>
</html>

 

效果图：

JS 获取域名部分_html