<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>canvas验证码</title> <style> .input-val { width: 200px; 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; } </style> </head> <body> <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> <script src="https://cdn.bootcss.com/jquery/1.11.1/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> </body> </html>