这是一个简单的js编写的验证码，自己已经亲自验证，没有问题了
1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 2 <html xmlns="http://www.w3.org/1999/xhtml"> 3 <head> 4 <title>js编写验证码</title> 5 <style type="text/css" > 6 7 .code 8 { 9 background-image:url(code.jpg); 10 font-family:Arial; 11 font-style:italic; 12 color:Red; 13 border:0; 14 padding:2px 3px; 15 letter-spacing:3px; 16 font-weight:bolder; 17 } 18 19 .unchanged 20 { 21 border:0; 22 } 23 </style> 24 <script language="javascript" type="text/javascript"> 25 var code ; //在全局 定义验证码 26 function createCode() 27 { 28 code = ""; 29 var codeLength = 6;//验证码的长度 30 var checkCode = document.getElementById("checkCode"); 31 var selectChar = new Array(0,1,2,3,4,5,6,7,8,9,'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z');//所有候选组成验证码的字符，当然也可以用中文的 32 for(var i=0;i<codeLength;i++) 33 { 34 35 var charIndex = Math.floor(Math.random()*36); //Math.random得到0-36中随机的一个数,floor取整数部分 36 code +=selectChar[charIndex]; 37 } 38 // alert(code); 39 if(checkCode) 40 { 41 checkCode.className="code"; 42 checkCode.value = code; 43 } 44 } 45 46 function validate () 47 { 48 49 var inputCode = document.getElementById("input1").value; 50 if(inputCode.length <=0) 51 { 52 alert("请输入验证码！"); 53 } 54 else if(inputCode != code ) 55 { 56 alert("验证码输入错误！"); 57 createCode();//刷新验证码 58 } 59 else 60 { 61 alert("^-^ OK"); 62 } 63 64 } 65 66 </script> 67 </head> 68 <body onload="createCode()" > 69 <form action="#"> 70 71 <input type="text" id="input1" /> 72 73 <input type="text" onclick="createCode()" readonly="readonly" id="checkCode" class="unchanged" style=" 80px" /><br /> 74 75 <input id="Button1" onclick="validate();" type="button" value="确定" /> 76 77 </form> 78 </body> 79 </html>
一定要在body出onload不然第一次加载的时候看不到验证码