自己用js做的一个简单的地图，可以实现拖动和放大缩小，为了使代码简单，其他功能都去掉了，适合初学者研究修改-I use js to make a simple map, can achieve drag and zooming, in order to make the code simple, other features are removed, suitable for beginners research review

实现了一个js的在线小测试，有时间限制，超时可超新测试一次。测试结束有分数及详细报告。-Js to achieve a small test online, there are time constraints, overtime can be a super-new test. The end of the test scores and a detailed report there.

通过js,判断当前浏览器是否联网,从而加载不同的js文件(Determine whether current browsers are connected)