<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>js+canvas实现任意字符生成图片验证码</title> <canvas id="canvas" width="120" height="40" class="codeImg" title="看不清，换一张"></canvas> </head> <body> <script> drawPic("1a2b3c4"); /**生成一个随机数**/ function randomNum(min, max) { return Math.floor(Math.random() * (max - min) + min); } /**生成一个随机色**/ function randomColor(min, max) { var r = randomNum(min, max); var g = randomNum(min, max); var b = randomNum(min, max); return "rgb(" + r + "," + g + "," + b + ")"; } /**绘制验证码图片**/ function drawPic(num) { var canvas = document.getElementById("canvas"); var width = canvas.width; var height = canvas.height; var ctx = canvas.getContext(‘2d‘); ctx.textBaseline = ‘bottom‘; /**绘制背景色**/ ctx.fillStyle = randomColor(180, 240); //颜色若太深可能导致看不清 ctx.fillRect(0, 0, width, height); /**绘制文字**/ var txt = num; ctx.fillStyle = randomColor(50, 160); //随机生成字体颜色 ctx.font = randomNum(25, 35) + ‘px SimHei‘; //随机生成字体大小 var x = 22; var y = 35; var deg = randomNum(-10, 8); //修改坐标原点和旋转角度 ctx.translate(x, y); ctx.rotate(deg * Math.PI / 180); ctx.fillText(txt, 0, 0); // //恢复坐标原点和旋转角度 ctx.rotate(-deg * Math.PI / 180); ctx.translate(-x, -y); /* } */ /* /**绘制干扰线**/ for (var i = 0; i < 8; i++) { ctx.strokeStyle = randomColor(40, 180); ctx.beginPath(); ctx.moveTo(randomNum(0, width), randomNum(0, height)); ctx.lineTo(randomNum(0, width), randomNum(0, height)); ctx.stroke(); } /**绘制干扰点**/ for (var i = 0; i < 100; i++) { ctx.fillStyle = randomColor(0, 255); ctx.beginPath(); ctx.arc(randomNum(0, width), randomNum(0, height), 1, 0, 2 * Math.PI); ctx.fill(); } } </script> </body> </html>