用ajax函数读取xml，然后解析XML.html，ajax无刷新读取文件，先使用jQuery加载XML,然后建立一个代码片段，遍历所有student节点，获取id节点，获取节点文本，获取student下的email属性，构造HTML字符串，通过append方法添加进之前建立代码片段，最后得到的frag添加进HTML文档中-Ajax function for reading xml, then parse XML.html, ajax no refresh to read the file, the first use jQuery to load XML, and then create a snippet, through all student nodes, get id node, get the node text, get the next student s email property, construct an HTML string, add the code snippet to establish before going through the append method, add the resulting HTML document frag