JavaScript+html實現(xiàn)前端頁面隨機二維碼驗證

更新時間：2021年06月06日 11:07:20 作者：蜜桃婷婷醬

這篇文章主要為大家詳細介紹了JavaScript+html實現(xiàn)前端頁面隨機二維碼驗證，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

分享炫酷的前端頁面隨機二維碼驗證，供大家參考，具體內(nèi)容如下

直接上代碼

<%@ 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="請輸入驗證碼（不區(qū)分大小寫）" 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('請輸入驗證碼！');
            }else if(val == num){
                alert('提交成功！');
                $(".input-val").val('');
                // draw(show_num);

            }else{
                alert('驗證碼錯誤！請重新輸入！');
                $(".input-val").val('');
                // draw(show_num);
            }
        })
    })

    //生成并渲染出驗證碼圖形
    function draw(show_num) {
        var canvas_width=$('#canvas').width();
        var canvas_height=$('#canvas').height();
        var canvas = document.getElementById("canvas");//獲取到canvas的對象，演員
        var context = canvas.getContext("2d");//獲取到canvas畫圖的環(huán)境，演員表演的舞臺
        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;//獲取到數(shù)組的長度

        for (var i = 0; i < 4; i++) {  //這里的for循環(huán)可以控制驗證碼位數(shù)（如果想顯示6位數(shù)，4改成6即可）
            var j = Math.floor(Math.random() * aLength);//獲取到隨機的索引值
            // var deg = Math.random() * 30 * Math.PI / 180;//產(chǎn)生0~30之間的隨機弧度
            var deg = Math.random() - 0.5; //產(chǎn)生一個隨機弧度
            var txt = aCode[j];//得到隨機的一個內(nèi)容
            show_num[i] = txt.toLowerCase();
            var x = 10 + i * 20;//文字在canvas上的x坐標
            var y = 20 + Math.random() * 8;//文字在canvas上的y坐標
            context.font = "bold 23px 微軟雅黑";

            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++) { //驗證碼上顯示線條
            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++) { //驗證碼上顯示小點
            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();
        }
    }

    //得到隨機的顏色值
    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