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  • js随机验证码

    <!DOCTYPE html>
    <html>
        <head>
            <meta charset="UTF-8">
            <meta name="viewport" content="width=device-width, initial-scale=1,maximum-scale=1,user-scalable=no">       
            <title>验证码生成示例</title>      
            <style>
                /*验证码*/
                .verificationCode{
                    width: 100px;
                    height: 40px;
                    position: absolute;
                    right: 0;
                    top:0;
                }
                canvas{
                    width: 100%;
                    height: 100%;
                }
                #code_img {
                    width: 100%;
                    height: 100%;
                    cursor: pointer;
                    vertical-align: top;
                }
                .input{
                    width: 100%;
                    height: 40px;
                    position: relative;
                }
                #verifital_input{
                    border: none;
                    border-bottom:1px solid #ccc;
                    outline: none;
                    height: 40px
                }
            </style>
        </head>
        <body>
            <div class="content">
                <div class="input">
                    <label>验证码:</label>
                    <input type="text" id="verifital_input"  placeholder="请输入验证码">
                    <div id="verificationCode" class="verificationCode">
                        <canvas width="100" height="40" id="verifyCanvas"></canvas>
                        <div width="100" height="40"> <img id="code_img"></div>                  
                    </div>
                </div>
            </div>
        </body>   
        <script type="text/javascript" src="js/jquery.js" ></script>
        <script type="text/javascript" src="js/verificationCode.js" ></script>
        <script>
            console.log(verVal)
        </script>
    </html>
    var nums = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0", 
        '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'
    ];
    var str = '';
    var verVal = drawCode();
    // 绘制验证码
    function drawCode (str) {
        var canvas = document.getElementById("verifyCanvas"); //获取HTML端画布
        var context = canvas.getContext("2d"); //获取画布2D上下文
        context.fillStyle = "cornflowerblue"; //画布填充色
        context.fillRect(0, 0, canvas.width, canvas.height); //清空画布
        context.fillStyle = "white"; //设置字体颜色
        context.font = "25px Arial"; //设置字体
        var rand = new Array();//数组获取的四位验证码
        var x = new Array();
        var y = new Array();
        for (var i = 0; i < 4; i++) {
            rand.push(rand[i]);
            rand[i] = nums[Math.floor(Math.random() * nums.length)]
            x[i] = i * 20 + 10;
            y[i] = Math.random() * 20 + 20;
            context.fillText(rand[i], x[i], y[i]);
        }
        str = rand.join('').toUpperCase();
        //画3条随机线
        for (var i = 0; i < 3; i++) {
            drawline(canvas, context);
        }
    
        // 画30个随机点
        for (var i = 0; i < 30; i++) {
            drawDot(canvas, context);
        }
        convertCanvasToImage(canvas);
        return str;
    }
    
    // 随机线
    function drawline (canvas, context) {
        context.moveTo(Math.floor(Math.random() * canvas.width), Math.floor(Math.random() * canvas.height)); //随机线的起点x坐标是画布x坐标0位置,y坐标是画布高度的随机数
        context.lineTo(Math.floor(Math.random() * canvas.width), Math.floor(Math.random() * canvas.height)); //随机线的终点x坐标是画布宽度,y坐标是画布高度的随机数
        context.lineWidth = 0.5; //随机线宽
        context.strokeStyle = 'rgba(50,50,50,0.3)'; //随机线描边属性
        context.stroke(); //描边,即起点描到终点
    }
    // 随机点(所谓画点其实就是画1px像素的线,方法不再赘述)
    function drawDot (canvas, context) {
        var px = Math.floor(Math.random() * canvas.width);
        var py = Math.floor(Math.random() * canvas.height);
        context.moveTo(px, py);
        context.lineTo(px + 1, py + 1);
        context.lineWidth = 0.2;
        context.stroke();
    
    }
    // 绘制图片
    function convertCanvasToImage (canvas) {
        document.getElementById("verifyCanvas").style.display = "none";
        var image = document.getElementById("code_img");
        image.src = canvas.toDataURL("image/png");
        return image;
    }
    
    // 点击图片刷新
    document.getElementById('code_img').onclick = function() {
        resetCode();
    }
    
    function resetCode () {
        $('#verifyCanvas').remove();
        $('#code_img').before('<canvas width="100" height="40" id="verifyCanvas"></canvas>')
        verVal = drawCode();
    }
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  • 原文地址:https://www.cnblogs.com/xiaobaibubai/p/13139943.html
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