JS实现图片验证码功能
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以下代码可以直接copy运行，不需要引入jquery.jar
1. html代码
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script src="<%=request.getContextPath()%>/js/gVerify.js"></script>
<style type="text/css">
body, html {width: 100%;text-align: center;
}
#picyzm {width: 100px;height: 40px;display: inline-block;margin: 0 30px;
}
#verifyCodeDemo {width: 100%;display: flex;margin-top: 200px;justify-content: center;
}
#btn {margin: 30px auto;background-color: blue;color: #fff;border-radius: 5px;border: 0;width: 100px;height: 40px;
}
</style>
</head>
<body><div id="verifyCodeDemo"><input type="text" id="code_input" placeholder="在这个框里输入验证码"><p id="picyzm"></p></div><input type="button" value="验证" id="btn"><script type="text/javascript">//初始化验证码var verifyCode = new GVerify({id : "picyzm",type : "blend"});//点击按钮验证var code = document.getElementById("code_input");var btn = document.getElementById("btn");btn.onclick = function() {var res = verifyCode.validate(code.value);if (res) {alert("验证通过");} else {alert("验证码错误");}}</script>
</body>
</html>
2. 引入gVerify.js
!(function(window, document) {function GVerify(options) { // 创建一个图形验证码对象，接收options对象为参数this.options = { // 默认options参数值id: "", // 容器IdcanvasId: "verifyCanvas", // canvas的IDwidth: "100", // 默认canvas宽度height: "30", // 默认canvas高度type: "blend", // 图形验证码默认类型blend:数字字母混合类型、number:纯数字、letter:纯字母code: ""}if(Object.prototype.toString.call(options) == "[object Object]"){// 判断传入参数类型for(var i in options) { // 根据传入的参数，修改默认参数值this.options[i] = options[i];}}else{this.options.id = options;}this.options.numArr = "0,1,2,3,4,5,6,7,8,9".split(",");this.options.letterArr = getAllLetter();this._init();this.refresh();}GVerify.prototype = {/** 版本号* */version: '1.0.0',/** 初始化方法* */_init: function() {var con = document.getElementById(this.options.id);var canvas = document.createElement("canvas");this.options.width = con.offsetWidth > 0 ? con.offsetWidth : "100";this.options.height = con.offsetHeight > 0 ? con.offsetHeight : "30";canvas.id = this.options.canvasId;canvas.width = this.options.width;canvas.height = this.options.height;canvas.style.cursor = "pointer";canvas.innerHTML = "您的浏览器版本不支持canvas";con.appendChild(canvas);var parent = this;canvas.onclick = function(){parent.refresh();}},/** 生成验证码* */refresh: function() {this.options.code = "";var canvas = document.getElementById(this.options.canvasId);if(canvas.getContext) {var ctx = canvas.getContext('2d');}else{return;}ctx.textBaseline = "middle";ctx.fillStyle = randomColor(180, 240);ctx.fillRect(0, 0, this.options.width, this.options.height);if(this.options.type == "blend") { // 判断验证码类型var txtArr = this.options.numArr.concat(this.options.letterArr);} else if(this.options.type == "number") {var txtArr = this.options.numArr;} else {var txtArr = this.options.letterArr;}for(var i = 1; i <= 4; i++) {var txt = txtArr[randomNum(0, txtArr.length)];this.options.code += txt;ctx.font = randomNum(this.options.height/2, this.options.height) + 'px SimHei'; // 随机生成字体大小ctx.fillStyle = randomColor(50, 160); // 随机生成字体颜色ctx.shadowOffsetX = randomNum(-3, 3);ctx.shadowOffsetY = randomNum(-3, 3);ctx.shadowBlur = randomNum(-3, 3);ctx.shadowColor = "rgba(0, 0, 0, 0.3)";var x = this.options.width / 5 * i;var y = this.options.height / 2;var deg = randomNum(-30, 30);/** 设置旋转角度和坐标原点* */ctx.translate(x, y);ctx.rotate(deg * Math.PI / 180);ctx.fillText(txt, 0, 0);/** 恢复旋转角度和坐标原点* */ctx.rotate(-deg * Math.PI / 180);ctx.translate(-x, -y);}/** 绘制干扰线* */for(var i = 0; i < 4; i++) {ctx.strokeStyle = randomColor(40, 180);ctx.beginPath();ctx.moveTo(randomNum(0, this.options.width), randomNum(0, this.options.height));ctx.lineTo(randomNum(0, this.options.width), randomNum(0, this.options.height));ctx.stroke();}/** 绘制干扰点* */for(var i = 0; i < this.options.width/4; i++) {ctx.fillStyle = randomColor(0, 255);ctx.beginPath();ctx.arc(randomNum(0, this.options.width), randomNum(0, this.options.height), 1, 0, 2 * Math.PI);ctx.fill();}},/** 验证验证码* */validate: function(code){var code = code.toLowerCase();var v_code = this.options.code.toLowerCase();if(code == v_code){return true;}else{return false;}}}/** 生成字母数组* */function getAllLetter() {var letterStr = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";return letterStr.split(",");}/** 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 + ")";}window.GVerify = GVerify;
})(window, document);
3. 效果图
