浏览器前端页面中，爬取另一个页面的html并取出相关数据
var txt = '<html><body>......</body></html>';
var parser = new DOMParser();
var xmlDoc = parser.parseFromString(txt, "text/html");
var $client = $(xmlDoc.getElementsByTagName("body")[0]).find('ul.article-ul li:first');
var id = $client.find('.wx-width:first span').text().trim();
var rank = $client.find('.wx-rank:first span').text().trim();