JavaScript 实现简易网速测试功能实例

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
 <title> New Document </title>
 <meta http-equiv="Content-Type" content="text/html; charset=gbk"/>
 <meta name="Generator" content="EditPlus">
 <meta name="Author" content="xinmingyang">
 <meta name="Keywords" content="">
 <meta name="Description" content="">
 </head>
 <body>
 <SCRIPT language=JavaScript>
   var st = new Date();
</SCRIPT>
<IMG alt="测试图片" src="https://www.jb51.net/images/logo.gif" onload="showspeed();">
<div id='showtxt'></div>
<script>
  var arr=["网速低于50KB","网速在50-100KB之间","网速在100-200KB之间","网速在200-300KB之间","视频通讯"];
  function showspeed() 
  { 
    var filesize =35.4;  //measured in KB  
    var et = new Date(); 
    var speed = Math.round(filesize*1000)/(et - st);
    document.title=speed;
    var scope=(speed>0 && speed<=50)?0:(speed>50 && speed<=100)?1:(speed>=100 && speed<200)?2:(speed>=200 && speed<300)?3:4;
    alert(scope)
    document.getElementById("showtxt").innerHTML = ("您的下载速度为：" + arr[scope] + " (K/秒)") 
  } 
</script>
 </body>
</html>