同为省市区三级联动菜单，但程序执行的效率是不一样的，前段时间因工作需要做的一个小东西，虽然小，但工作量很大，因为全国的省市区数据全部集中在XML文件中，这样避免了存储在数据库中给页面读取造成的压力，地市信息是最新的，配全JS调用程序，使其不占用系统资源，速度快捷方便，直接放到你的网站目录就可调用。-Three linkage with the provinces menu, but the efficiency of program execution is not the same, some time ago because of work needs to be done a little thing, though small, but a lot of work, because the urban data all concentrated in the provinces of XML file, thus avoiding pressure stored in the　to read the page caused, city information is up to date with all-JS calling program, it does not take up system resources, speed fast and convenient, directly into your Web directory you can call.