JavaScript+html实现前端页面随机二维码验证

分享炫酷的前端页面随机二维码验证，供大家参考，具体内容如下
直接上代码
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
    <!--引入jquery的js -->
    <script type="text/javascript" src="../jquery/jquery.js"></script>
</head>
<style>
    .input-val {
        width: 200px;
        height: 32px;
        border: 1px solid #ddd;
        box-sizing: border-box;
    }
    #canvas {
        vertical-align: middle;
        box-sizing: border-box;
        border: 1px solid #ddd;
        cursor: pointer;
    }
    .btn {
        display: block;
        margin-top: 20px;
        height: 32px;
        width: 100px;
        font-size: 16px;
        color: #fff;
        background-color: #457adb;
        border: none;
        border-radius: 50px;
    }
</style>
<body>
<div class="code">
    <input type="text" value="" placeholder="请输入验证码（不区分大小写）" class="input-val">
    <canvas id="canvas" width="100" height="30"></canvas>
    <button class="btn">提交</button>
</div>
</body>
<script>
    $(function(){
        var show_num = [];
        draw(show_num);

        $("#canvas").on('click',function(){
            draw(show_num);
        })
        $(".btn").on('click',function(){
            var val = $(".input-val").val().toLowerCase();
            var num = show_num.join("");
            if(val==''){
                alert('请输入验证码！');
            }else if(val == num){
                alert('提交成功！');
                $(".input-val").val('');
                // draw(show_num);

            }else{
                alert('验证码错误！请重新输入！');
                $(".input-val").val('');
                // draw(show_num);
            }
        })
    })

    //生成并渲染出验证码图形
    function draw(show_num) {
        var canvas_width=$('#canvas').width();
        var canvas_height=$('#canvas').height();
        var canvas = document.getElementById("canvas");//获取到canvas的对象，演员
        var context = canvas.getContext("2d");//获取到canvas画图的环境，演员表演的舞台
        canvas.width = canvas_width;
        canvas.height = canvas_height;
        var sCode = "a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
        var aCode = sCode.split(",");
        var aLength = aCode.length;//获取到数组的长度

        for (var i = 0; i < 4; i++) {  //这里的for循环可以控制验证码位数（如果想显示6位数，4改成6即可）
            var j = Math.floor(Math.random() * aLength);//获取到随机的索引值
            // var deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度
            var deg = Math.random() - 0.5; //产生一个随机弧度
            var txt = aCode[j];//得到随机的一个内容
            show_num[i] = txt.toLowerCase();
            var x = 10 + i * 20;//文字在canvas上的x坐标
            var y = 20 + Math.random() * 8;//文字在canvas上的y坐标
            context.font = "bold 23px 微软雅黑";

            context.translate(x, y);
            context.rotate(deg);

            context.fillStyle = randomColor();
            context.fillText(txt, 0, 0);

            context.rotate(-deg);
            context.translate(-x, -y);
        }
        for (var i = 0; i <= 5; i++) { //验证码上显示线条
            context.strokeStyle = randomColor();
            context.beginPath();
            context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
            context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
            context.stroke();
        }
        for (var i = 0; i <= 30; i++) { //验证码上显示小点
            context.strokeStyle = randomColor();
            context.beginPath();
            var x = Math.random() * canvas_width;
            var y = Math.random() * canvas_height;
            context.moveTo(x, y);
            context.lineTo(x + 1, y + 1);
            context.stroke();
        }
    }

    //得到随机的颜色值
    function randomColor() {
        var r = Math.floor(Math.random() * 256);
        var g = Math.floor(Math.random() * 256);
        var b = Math.floor(Math.random() * 256);
        return "rgb(" + r + "," + g + "," + b + ")";
    }

</script>
</html>
效果如下
JavaScript+html实现前端页面随机二维码验证
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持NICE源码。
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