效果如下：
复制代码代码如下: <html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server"> <title></title> <style type="text/css"> .code { background:url(code_bg.jpg); font-family:Arial; font-style:italic; color:blue; font-size:30px; border:0; padding:2px 3px; letter-spacing:3px; font-weight:bolder; float:left; cursor:pointer; width:150px; height:60px; line-height:60px; text-align:center; vertical-align:middle; } a { text-decoration:none; font-size:12px; color:#288bc4; } a:hover { text-decoration:underline; } </style> <script language="javascript" type="text/javascript"> var code; function createCode() { code = ""; var codeLength = 6; //验证码的长度 var checkCode = document.getElementById("checkCode"); var codeChars = 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', '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 for (var i = 0; i < codeLength; i++) { var charNum = Math.floor(Math.random() * 52); code += codeChars[charNum]; } if (checkCode) { checkCode.className = "code"; checkCode.innerHTML = code; } } function validateCode() { var inputCode = document.getElementById("inputCode").value; if (inputCode.length <= 0) { alert("请输入验证码！"); } else if (inputCode.toUpperCase() != code.toUpperCase()) { alert("验证码输入有误！"); createCode(); } else { alert("验证码正确！"); } } </script> </head> <body οnlοad="createCode()"> <form id="form1" runat="server" οnsubmit="validateCode()"> <div> <table border="0" cellspacing="5" cellpadding="5" > <tr> <td></td><td> <div class="code" id="checkCode" οnclick="createCode()" ></div></td> <td><a href="#" οnclick="createCode()">看不清换一张</a></td> </tr> <tr> <td>验证码：</td><td><input style="float:left;" type="text" id="inputCode" /></td><td>请输入验证码</td> </tr> <tr><td></td><td><input id="Button1" οnclick="validateCode();" type="button" value="确定" /></td><td></td> </tr> </table> </div> </form> </body> </html>
