页面canvas验证

页面验证canvas验证生成

<div class="code">
      <input
        type="text"
        value=""
        placeholder="请输入验证码（不区分大小写）"
        class="input-val"
      />
      <canvas id="canvas" width="100" height="30">canvas>
      <button class="btn">提交button>
    div>

样式代码css

JavaScript代码

<script src="http://libs.baidu.com/jquery/1.7.2/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("");
        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，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,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(",");
      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
        // 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>

这里只有生成canvas的代码剩下的大家自己成长，毕竟有很多开源不需要VIP的文章