Jquery随机验证码

代码

需要引入Jquery文件

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>jq随机图形二维码</title>
<script src="jquery.min.js"></script>
<style>
#verify {
    height:34px;
    vertical-align:top;
    font-size:16px;
}
#code_img {
    width:100px;
    height:40px;
    cursor:pointer;
    vertical-align:top;
}
</style>
</head>
<body>
点击图片重新生成验证码
    <p>
        <input type="text" class="topAlign" id="verify" name="verify" required="">
        <canvas width="100" height="40" id="verifyCanvas"></canvas>
        <img id="code_img">
    </p>
    <button id="submit" type="submit">提交</button>


<script>
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 colors = []
drawCode();
// 绘制验证码
function drawCode() {
    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 = "blanchedalmond"; //画布填充色
    context.fillRect(0, 0, canvas.width, canvas.height);
    // 创建渐变
    var gradient = context.createLinearGradient(0, 0, canvas.width, 0);
    gradient.addColorStop("0", "magenta");
    gradient.addColorStop("0.5", "blue");
    gradient.addColorStop("1.0", "red");
    //清空画布
    context.fillStyle = gradient; //设置字体颜色
    context.font = "25px Arial"; //设置字体
    var rand = new Array();
    var x = new Array();
    var y = new Array();
    for (var i = 0; i < 4; i++) {
        rand[i] = nums[Math.floor(Math.random() * nums.length)]
        x[i] = i * 16 + 10;
        y[i] = Math.random() * 20 + 20;
        context.fillText(rand[i], x[i], y[i]);
    }
    // console.log(rand);
    //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)


    // 点击提交进行验证
    // $("#submit").click((e) => {
    //     var newRand = rand.join('').toUpperCase();
    //     console.log(newRand);

    //     //下面就是判断是否== 的代码，无需解释
    //     var oValue = $('#verify').val().toUpperCase();
    //     console.log(oValue)
    //     if (oValue == 0) {} else if (oValue != newRand) {
    //         oValue = ' ';
    //     } else {
    //         window.open('http://www.baidu.com', '_self');
    //     }

    // })
}

// 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() {
    $('#verifyCanvas').remove();
    $('#verify').after('<canvas width="100" height="40" id="verifyCanvas"></canvas>')
    drawCode();
}
</script>

</body>
</html>