前端HTML+Jquery生成验证码

一、HTML代码

<canvas id="canvas" style="cursor:pointer;width: 120px;height: 40px;" onclick="Generate()"></canvas>

二、JavaScript代码

var show_num = []; //存放验证码

 $(function () {
     Draw(show_num); //绘制验证码
 });

//重新生成验证码
    function Generate() {
        show_num = []; //清空数组
        Draw(show_num);
    };

// 绘制验证码
    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,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 <= 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
            //show_num[i] = txt.toLowerCase(); //转成小写，不区分大小写
            show_num[i] = txt; //精准匹配
            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();
        }
    }

    function 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 + ")";
    }