前言

老早就想搞个图片验证码了，虽然没有目前来讲垃圾评论但是还是想搞，之前也看到好多博友被刷垃圾评论。于是白天懒得搞，一到晚上就精神焕发，再于是就去网上查找了一番，但是发现，如果验证码 input 被删除了，就不用输验证码也能评论，于是又花了一会时间，修改了一下，删除了就不能提交了，最后大功告成！！！

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: "comment-form", //容器Id
            canvasId: "verifyCanvas", //canvas的ID
            width: "100", //默认canvas宽度
            height: "38", //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 = "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 : "38";
            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){
                alert('运气不错呀，这么难都答对啦!')
                
                return true;
            }else{
                alert('运气不太好呀，重新输一下吧~~')
                document.getElementById("viewInpt").value="";
                // this.refresh(); 禁止自动刷新
                return false;
                
            }
        }
    }
    /**生成字母数组**/
    function getAllLetter() {
        var letterStr = "a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,J,K,L,M,N,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);

   var gVerify=new GVerify("view");//传入你要把验证码的图片生成的位置的id
    function yanzheng(){
      var str=$("#viewInpt").val()//获取输入框内容
      console.log(gVerify.validate(str))//验证输入的验证码是否正确
        }
        
        
 function validateCaptcha() {
    var input = document.getElementById("viewInpt").value;
  }
// 使用事件监听器来捕获表单提交事件
  var form = document.querySelector("form");
  form.addEventListener("submit", function (event) {
    // 阻止默认的表单提交行为
    event.preventDefault();

    // 执行您想要的功能
    validateCaptcha();

    // 如果验证成功，则手动提交表单
    if (validateCaptcha() == true) {
       alert('运气不太好呀，重新输一下吧~~')
    } else {
        form.submit();
      alert('稍等片刻 努力提交数据~~')
    }
  });

Html

   <input type="text"  id="viewInpt" onblur="yanzheng()"  placeholder="请输入图片验证码" required="required">

问答悬赏

然后问答模式修改成了问答悬赏再 PC 端的左侧显示，不然老是白嫖，感觉有点浪费别人时间，对问题也是会提高一些效率吧！