原生js生成图片验证码

本文实例为大家分享了js生成图片验证码的具体代码，供大家参考，具体内容如下

html代码

<!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/picCode.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>

!(function(window, document) {
 var size = 5;//设置验证码长度
 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 <=size; 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 / (size+1) * 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{
    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);

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自学编程网。

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