纯前端生成验证码-蒲公英云

纯前端生成验证码

生成验证码的方法：

function code_draw() {
    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,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"; //取值范围
    var aCode = sCode.split(",");
    var aLength = aCode.length; //获取到数组的长度
    var value = [];
    for (var i = 0; i <= 3; i++) {
        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 txt = aCode[j]; //得到随机的一个内容
        value[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 = code_randomColor();
        context.fillText(txt,0);
        context.rotate(-deg);
        context.translate(-x,-y);
    }
    // 将生成的值以属性的方法添加到元素
    value = value.join("");
    $('#canvas').attr('data-code',value)
    //验证码上显示线条
    for (var i = 0; i <= 5; i++) {
        context.strokeStyle = code_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();
    }
    //验证码上显示小点
    for (var i = 0; i <= 30; i++) {
        context.strokeStyle = code_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();
    }
}

生成验证码随机背景颜色：

function code_randomColor() {
     //得到随机的颜色值
    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 + ")";
}

在html中引用：

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <Meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title>jQuery canvas验证码</title>
        <style type="text/css">
            * {
                margin: 0;
                padding: 0;
                Box-sizing: border-Box;
            }
            html {
                width: 100%;
                height: 100%;
                font-size: 16px;
            }
            body {
                width: 100%;
                height: 100%;
                -moz-user-select: none;
                /*火狐*/
                /*禁止用户在页面选择文字*/
                -webkit-user-select: none;
                /*webkit浏览器*/
                -ms-user-select: none;
                /*IE10*/
                -khtml-user-select: none;
                /*早期浏览器*/
                user-select: none;
            }
            .code {
                padding-top: 50px;
                width: 400px;
                margin: 0 auto;
            }
            .input-val {
                width: 295px;
                background: #ffffff;
                height: 2.8rem;
                padding: 0 2%;
                border-radius: 5px;
                border: none;
                border: 1px solid rgba(0,.2);
                font-size: 1.0625rem;
            }
            #canvas {
                float: right;
                display: inline-block;
                border: 1px solid #ccc;
                border-radius: 5px;
                cursor: pointer;
            }
            .btn {
                width: 100px;
                height: 40px;
                background: #f1f1f1;
                border: 1px solid #ccc;
                border-radius: 5px;
                margin: 20px auto 0;
                display: block;
                font-size: 1.2rem;
                color: #e22e1c;
                cursor: pointer;
            }
        </style>
    </head>
    <body>
        <div class="code">
            <input type="text" value="" placeholder="验证码" class="input-val" />
            <canvas id="canvas" width="100" height="43"></canvas>
            <button class="btn">提交</button>
        </div>
    </body>