JavaScript生成图形验证码

本文实例为大家分享了js生成图形验证码的具体代码，供大家参考，具体内容如下

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;
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。