如何用js生成简单验证码，并验证是否正确的方法
1、html页面如下
<div><table border="0" cellspacing="5" cellpadding="5" ><tr><td> <div id="checkCode" class="code" onclick="createCode(4)" ></div></td><td> <span onclick="createCode(4)">看不清换一张</span></td></tr><tr><td>验证码：</td><td><input type="text" id="inputCode" style="float:left;" /></td></tr><tr><td></td><td><input type="button" onclick="validateCode()" value="确定" /></td></tr></table></div>2、js脚本如下
//页面加载时，生成随机验证码window.onload=function(){createCode(4); }//生成验证码的方法function createCode(length) {var code = "";var codeLength = parseInt(length); //验证码的长度var checkCode = document.getElementById("checkCode");所有候选组成验证码的字符，当然也可以用中文的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'); //循环组成验证码的字符串for (var i = 0; i < codeLength; i++){//获取随机验证码下标var charNum = Math.floor(Math.random() * 62);//组合成指定字符验证码code += codeChars[charNum];}if (checkCode){//为验证码区域添加样式名checkCode.className = "code";//将生成验证码赋值到显示区checkCode.innerHTML = code;}}//检查验证码是否正确function validateCode(){//获取显示区生成的验证码var checkCode = document.getElementById("checkCode").innerHTML;//获取输入的验证码var inputCode = document.getElementById("inputCode").value;//console.log(checkCode);//console.log(inputCode);if (inputCode.length <= 0){alert("请输入验证码！");}else if (inputCode.toUpperCase() != checkCode.toUpperCase()){alert("验证码输入有误！");createCode(4);}else{alert("验证码正确！");} }3、验证码效果图如下：
注：createCode可以传递参数，决定生成验证码的位数
4、整体demo源码：
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>js简单验证码使用</title>
<style>.code{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:50px;line-height:60px;text-align:center;vertical-align:middle;background-color:#D8B7E3;}span {text-decoration:none;font-size:12px;color:#288bc4;padding-left:10px;}span:hover {text-decoration:underline;cursor:pointer;}</style>
</head>
<script>//页面加载时，生成随机验证码window.onload=function(){createCode(4); }//生成验证码的方法function createCode(length) {var code = "";var codeLength = parseInt(length); //验证码的长度var checkCode = document.getElementById("checkCode");所有候选组成验证码的字符，当然也可以用中文的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'); //循环组成验证码的字符串for (var i = 0; i < codeLength; i++){//获取随机验证码下标var charNum = Math.floor(Math.random() * 62);//组合成指定字符验证码code += codeChars[charNum];}if (checkCode){//为验证码区域添加样式名checkCode.className = "code";//将生成验证码赋值到显示区checkCode.innerHTML = code;}}//检查验证码是否正确function validateCode(){//获取显示区生成的验证码var checkCode = document.getElementById("checkCode").innerHTML;//获取输入的验证码var inputCode = document.getElementById("inputCode").value;console.log(checkCode);console.log(inputCode);if (inputCode.length <= 0){alert("请输入验证码！");}else if (inputCode.toUpperCase() != checkCode.toUpperCase()){alert("验证码输入有误！");createCode(4);}else{alert("验证码正确！");} }
</script>
<body><div><table border="0" cellspacing="5" cellpadding="5" ><tr><td> <div id="checkCode" class="code" onclick="createCode(4)" ></div></td><td> <span onclick="createCode(4)">看不清换一张</span></td></tr><tr><td>验证码：</td><td><input type="text" id="inputCode" style="float:left;" /></td></tr><tr><td></td><td><input type="button" onclick="validateCode()" value="确定" /></td></tr></table></div>
</body>
</html>平时多记记，到用时才能看看，记录你的进步，分享你的成果
