前端页面-验证码

  • 仅前端html实现
  • <!DOCTYPE html>
    <html >
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>发送验证码</title>
    <style>
    .contain{
    width:400px;
    height:200px;
    margin:100px auto;
    }
    .input-val {
    width: 120px;
    height: 32px;
    border: 1px solid #ddd;
    box-sizing: border-box;
    }
    #canvas {
    vertical-align: middle;
    box-sizing: border-box;
    border: 1px solid #ddd;
    cursor: pointer;
    }
    .btn {
    display: block;
    margin-top: 20px;
    height: 32px;
    width: 100px;
    font-size: 16px;
    color: #fff;
    background-color: #457adb;
    border: none;
    border-radius: 50px;
    }
    </style>
    </head>
    <body>
    <div class="contain">
    <div class="code">
    <input type="text" value="" placeholder="请输入验证码" class="input-val">
    <canvas id="canvas" width="100" height="30"></canvas>
    <button class="btn">提交</button>
    </div>
    </div>
    <script src="http://www.lanrenzhijia.com/ajaxjs/jquery.min.js"></script>
    <script>
    $(function(){
    var show_num = [];
    draw(show_num);
    $("#canvas").on('click',function(){
    draw(show_num);
    })
    $(".btn").on('click',function(){
    var val = $(".input-val").val().toLowerCase();
    var num = show_num.join(""); //用于把数组中的所有元素放入一个字符串。
    if(val==''){
    alert('请输入验证码!');
    }else if(val == num){
    alert('提交成功!');
    $(".input-val").val('');
    // draw(show_num);
    }else{
    alert('验证码错误!请重新输入!');
    $(".input-val").val('');
    // draw(show_num);
    }
    })
    })
    //生成并渲染出验证码图形
    function draw(show_num) {
    var canvas_width=$('#canvas').width();
    var canvas_height=$('#canvas').height();
    var canvas = document.getElementById("canvas");//获取到canvas的对象
    var context = canvas.getContext("2d");//获取到canvas画图的环境
    canvas.width = canvas_width;
    canvas.height = canvas_height;
    var sCode = "a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,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(","); //把字符串分割成字符串数组。
    var aLength = aCode.length;//获取到数组的长度
    for (var i = 0; i < 4; i++) { //这里的for循环可以控制验证码位数(如果想显示6位数,4改成6即可)
    var j = Math.floor(Math.random() * aLength);//获取到随机的索引值,random() 方法可返回介于 0(包含) ~ 1(不包含) 之间的一个随机数。
    // var deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度
    var deg = Math.random() - 0.5; //产生一个随机弧度
    var txt = aCode[j];//得到随机的一个内容
    show_num[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 = 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();
    }
    }
    //得到随机的颜色值
    function randomColor() {
    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 + ")";
    }
    </script>
    </body>
    </html>
posted @ 2022-02-22 11:10  subtlman  阅读(132)  评论(0)    收藏  举报