1. <!DOCTYPE html>
    2. <html >
    3. <head>
    4. <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    5. <title>发送验证码</title>
    6. <style>
    7.   .contain{
    8.     width:400px;
    9.     height:200px;
    10.     margin:100px auto;
    11.   }
    12.   .input-val {
    13.     width: 120px;
    14.     height: 32px;
    15.     border: 1px solid #ddd;
    16.     box-sizing: border-box;
    17.   }
    18.   #canvas {
    19.     vertical-align: middle;
    20.     box-sizing: border-box;
    21.     border: 1px solid #ddd;
    22.     cursor: pointer;
    23.   }
    24.   .btn {
    25.     display: block;
    26.     margin-top: 20px;
    27.     height: 32px;
    28.     width: 100px;
    29.     font-size: 16px;
    30.     color: #fff;
    31.     background-color: #457adb;
    32.     border: none;
    33.     border-radius: 50px;
    34.   }
    35. </style>
    36. </head>
    37. <body>
    38. <div class="contain">
    39.     <div class="code">
    40.       <input type="text" value="" placeholder="请输入验证码" class="input-val">
    41.       <canvas id="canvas" width="100" height="30"></canvas>
    42.       <button class="btn">提交</button>
    43.     </div>
    44. </div>
    45. <script src="http://www.lanrenzhijia.com/ajaxjs/jquery.min.js"></script>
    46. <script>
    47.  $(function(){
    48.   var show_num = [];
    49.   draw(show_num);
    50.   $("#canvas").on('click',function(){
    51.    draw(show_num);
    52.   })
    53.   $(".btn").on('click',function(){
    54.    var val = $(".input-val").val().toLowerCase();
    55.    var num = show_num.join("");   //用于把数组中的所有元素放入一个字符串。
    56.    if(val==''){
    57.     alert('请输入验证码！');
    58.    }else if(val == num){
    59.     alert('提交成功！');
    60.     $(".input-val").val('');
    61.     // draw(show_num);
    62.    }else{
    63.     alert('验证码错误！请重新输入！');
    64.     $(".input-val").val('');
    65.     // draw(show_num);
    66.    }
    67.   })
    68.  })
    69.  //生成并渲染出验证码图形
    70.  function draw(show_num) {
    71.   var canvas_width=$('#canvas').width();
    72.   var canvas_height=$('#canvas').height();
    73.   var canvas = document.getElementById("canvas");//获取到canvas的对象
    74.   var context = canvas.getContext("2d");//获取到canvas画图的环境
    75.   canvas.width = canvas_width;
    76.   canvas.height = canvas_height;
    77.   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";
    78.   var aCode = sCode.split(",");  //把字符串分割成字符串数组。
    79.   var aLength = aCode.length;//获取到数组的长度
    80.   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）
    81.    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。
    82.    // var deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度
    83.    var deg = Math.random() - 0.5; //产生一个随机弧度
    84.    var txt = aCode[j];//得到随机的一个内容
    85.    show_num[i] = txt.toLowerCase();
    86.    var x = 10 + i * 20;//文字在canvas上的x坐标
    87.    var y = 20 + Math.random() * 8;//文字在canvas上的y坐标
    88.    context.font = "bold 23px 微软雅黑";
    89.    context.translate(x, y);
    90.    context.rotate(deg);
    91.    context.fillStyle = randomColor();
    92.    context.fillText(txt, 0, 0);
    93.    context.rotate(-deg);
    94.    context.translate(-x, -y);
    95.   }
    96.   for (var i = 0; i <= 5; i++) { //验证码上显示线条
    97.    context.strokeStyle = randomColor();
    98.    context.beginPath();
    99.    context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
    100.    context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
    101.    context.stroke();
    102.   }
    103.   for (var i = 0; i <= 30; i++) { //验证码上显示小点
    104.    context.strokeStyle = randomColor();
    105.    context.beginPath();
    106.    var x = Math.random() * canvas_width;
    107.    var y = Math.random() * canvas_height;
    108.    context.moveTo(x, y);
    109.    context.lineTo(x + 1, y + 1);
    110.    context.stroke();
    111.   }
    112.  }
    113.  //得到随机的颜色值
    114.  function randomColor() {
    115.   var r = Math.floor(Math.random() * 256);
    116.   var g = Math.floor(Math.random() * 256);
    117.   var b = Math.floor(Math.random() * 256);
    118.   return "rgb(" + r + "," + g + "," + b + ")";
    119.  }
    120. </script>
    121. </body>
    122. </html>