JS 实现验证码

淩亂°似流年 2022-08-20 07:24 204阅读 0赞

<html>  
        <head>  
            <title>验证码</title>  
            <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
            <style type="text/css">  
                #code  
                {  
                    font-family:Arial;  
                    font-style:italic;  
                    font-weight:bold;  
                    border:0;  
                    letter-spacing:2px;  
                    color:blue;  
                }  
            </style>  
    
            </script>  
        </head>  
        <body>  
            <div>  
                <input type = "text" id = "input"/>  
                <input type = "button" id="code" οnclick="createCode()"/>  
                <input type = "button" value = "验证" onclick = "validate()"/>  
            </div>  
        </body>  
    	
    	<script type="text/javascript">
    	var code ; //在全局定义验证码   
    	
    	window.onload = createCode();
    //产生验证码  
    function createCode(){  
         code = "";   
         var codeLength = 4;//验证码的长度  
         var checkCode = document.getElementById("code");   
         var random = 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');//随机数  
         for(var i = 0; i < codeLength; i++) {//循环操作  
            var index = Math.floor(Math.random()*36);//取得随机数的索引（0~35）  
            code += random[index];//根据索引取得随机数加到code上  
        }  
        checkCode.value = code;//把code值赋给验证码  
    }  
    //校验验证码  
    function validate(){  
        var inputCode = document.getElementById("input").value.toUpperCase(); //取得输入的验证码并转化为大写        
        if(inputCode.length <= 0) { //若输入的验证码长度为0  
            alert("请输入验证码！"); //则弹出请输入验证码  
        }         
        else if(inputCode != code ) { //若输入的验证码与产生的验证码不一致时  
            alert("验证码输入错误！@_@"); //则弹出验证码输入错误  
            createCode();//刷新验证码  
            document.getElementById("input").value = "";//清空文本框  
        }         
        else { //输入正确时  
            alert("^-^"); //弹出^-^  
        }             
    }  
    	</script>
    </html>