<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <script type="text/javascript"> //产生一个四位的验证码。 function createCode(){ var datas = ['A','B','何','敏','凡','江','1','9']; // 0-7 长度8 var code = ""; for(var i = 0 ; i<4; i++){ //随机产生四个索引值 var index = Math.floor(Math.random()*datas.length); // random 0.0-1.0（不包括1.0） code+=datas[index]; } var spanNode = document.getElementById("code"); spanNode.innerHTML = code; spanNode.style.fontSize ="24px"; spanNode.style.color = "red"; spanNode.style.backgroundColor="gray"; spanNode.style.textDecoration = "line-through"; } function ready(){ createCode(); } </script> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>无标题文档</title> </head> <body onload="ready()"> <span id="code"></span><a href="#" onclick="createCode()">看不清，换一个</a> </body> </html>