Js图片验证码

效果图

Html代码

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate" />
    <meta http-equiv="Pragma" content="no-cache" />
    <meta http-equiv="Expires" content="0" />
    <meta name="viewport" content="width=device-width, initial-scale=1,maximum-scale=1,user-scalable=no">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-status-bar-style" content="black">
    <title>js依赖mui.css生成图片验证码</title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/mui/3.7.1/css/mui.min.css" />
    <style>
        #verifital_input {
            border:1px solid black;
        }
        /*验证码*/
        .verificationCode{
            width: 4rem;
            height: 100%;
            position: absolute;
            right: 0;
        }
        canvas{
            width: 100%;
            height: 100%;
        }
        #code_img {
            width: 100%;
            height: 100%;
            cursor: pointer;
            vertical-align: top;
        }
    </style>
</head>
<body>
    <div class="mui-content">
        <div class="mui-input-row login_input" style="width:300px;">
            <label>验证码</label>
            <input type="text" id="verifital_input" class="mui-input" placeholder="请输入验证码">
            <div id="verificationCode" class="verificationCode">
                <canvas width="100" height="40" id="verifyCanvas"></canvas>
                <img id="code_img">
            </div>
        </div>
    </div>
</body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/mui/3.7.1/js/mui.min.js" /></script>
<script src="https://lib.baomitu.com/jquery/3.4.1/jquery.js"></script>
<script type="text/javascript" >
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'];
//验证码大写变量
var str = '';
//验证码声明变量
var verVal = 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 = "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();
    var x = new Array();
    var y = new Array();
    //生成四位验证码
    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]);
    }
    //将验证码转化为大写并赋值给str
    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);
    }
    //绘制图片
    convertCanvasToImage(canvas);
}
// 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();
}
//重置验证码
function resetCode () {
    $('#verifyCanvas').remove();
    $('#code_img').before('<canvas width="100" height="40" id="verifyCanvas"></canvas>')
    //重新生成验证码
    verVal = drawCode();
}
document.getElementById("verifital_input").addEventListener("change",validate);
//验证事件
function validate(){
    var inputCode = document.getElementById("verifital_input").value.toUpperCase(); //取得输入的验证码并转化为大写
    if(inputCode.length <= 0) { //若输入的验证码长度为0
    alert("请输入验证码！"); //则弹出请输入验证码
    $("#verifital_input").focus();
    } else if(inputCode != str ) { //若输入的验证码与产生的验证码不一致时
        alert("验证码输入错误！@_@"); //则弹出验证码输入错误
        resetCode();//刷新验证码
        $("#verifital_input").val("");//清空文本框
        $("#verifital_input").focus();//重新聚焦验证码框
    } else { //输入正确时
        $("#verifyCanvas").blur();//绑定验证码输入正确时要做的事
        alert("验证码正确！");
    }
};
</script>
</html>
posted @ 2019-12-06 12:00 踏步阅读(553) 评论(0) 编辑收藏举报
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