前端随机验证码

蔚落 2021-09-02 05:12 478阅读 0赞

# [前端随机验证码 ][Link 1] #

前端登录或者注册的时候经常会有一个验证码，数字或者字母，本验证码是基于canves的。

使用方法：

<!DOCTYPE html>
    <html>
        <head>
            <meta charset="UTF-8">
            <title>图形验证码</title>
        </head>
        <body>
            <div id="v_container" style="width: 200px;height: 50px;"></div>
            <input type="text" id="code_input" value="" placeholder="请输入验证码"/><button id="my_button">验证</button>
        </body>
        <script src="js/gVerify.js"></script>
        <script>
            var verifyCode = new GVerify("v_container");
    
            document.getElementById("my_button").onclick = function(){
                var res = verifyCode.validate(document.getElementById("code_input").value);
                if(res){
                    alert("验证正确");
                }else{
                    alert("验证码错误");
                }
            }
        </script>
    </html>

使用很简单，截图如下

![41eb344fdbd2a5a9ebc59aac0bb71330.png][]

js代码如下：

!(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Id
                canvasId: "verifyCanvas", //canvas的ID
                width: "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();
                console.log(v_code);
                if(code == v_code){
                    return true;
                }else{
                    this.refresh();
                    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);

[Link 1]: https://www.cnblogs.com/haonanZhang/p/8658232.html
[41eb344fdbd2a5a9ebc59aac0bb71330.png]: /images/20210813/663144dadffc436aad39729a9dc5e350.png