<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> h1{ text-align: center; } </style> </head> <body> <div id="clock"> 倒计时：<span>10</span>秒 </div> <h1></h1> <script type="text/javascript"> var h1=document.querySelector("h1") var html=document.querySelector("html") var charcode; var num=0; var time=10; function rand(){ var random = parseInt(Math.random()*26) charcode=65+random; //数字转换成字符 var str = String.fromCharCode(charcode) h1.innerHTML=str; } rand() //键盘按键事件 html.onkeydown=function(e){ if(charcode==e.keyCode) {num++; rand() h1.style.color="#FFFF00" //文本阴影 h1.style.textShadow="blue" } else{ rand() h1.style.color="red" } } //计时器 var clock= setInterval(function(){ var span=document.querySelector("span") time--; span.innerHTML=time if(time==0) { //删除计时器 clearInterval(clock) alert("你每分钟能打"+num*6+"字！！！") } },1000) </script> </body> </html>
原文：https://www.cnblogs.com/a155-/p/12237894.html