JavaScript生成图形验证码

getGVerify:function (id)
    {

        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');
                }
                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 = '20px SimHei';
                    //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/2), randomNum(0, this.options.height/2));
                    ctx.lineTo(randomNum(0, this.options.width/2), 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 verifyCode = code.toLowerCase();
                var v_code = this.options.code.toLowerCase();
                if(verifyCode == 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 + ")";
        }

        return new GVerify(id);
    }

 调用方法

var verifyCode = new GVerify(id);

 验证方法

if(verifyCode.validate(inputCode)){
     return true;
}esle{
     return false;
}