原生js生成圖片驗證碼

阿新 • • 發佈：2020-10-13

本文例項為大家分享了js生成圖片驗證碼的具體程式碼，供大家參考，具體內容如下

html程式碼

<!DOCTYPE html>
<html>
 <head>
  <meta charset="UTF-8">
  <title>圖形驗證碼</title>
 </head>
 <body>
  <div id="v_container" style="width: 200px;height: 50px;"></div>
  <input type="text" id="code_input" value="" placeholder="請輸入驗證碼"/><button id="my_button">驗證</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("驗證正確");
   }else{
    alert("驗證碼錯誤");
   }
  }
 </script>
</html>

!(function(window,document) {
 var size = 5;//設定驗證碼長度
 function GVerify(options) { //建立一個圖形驗證碼物件，接收options物件為引數
  this.options = { //預設options引數值
   id: "",//容器Id
   canvasId: "verifyCanvas",//canvas的ID
   width: "100",//預設canvas寬度
   height: "30",//預設canvas高度
   type: "blend",//圖形驗證碼預設型別blend:數字字母混合型別、number:純數字、letter:純字母
   code: "",}
  if(Object.prototype.toString.call(options) == "[object Object]"){//判斷傳入引數型別
   for(var i in options) { //根據傳入的引數，修改預設引數值
    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 = {
  /**版本號**/
  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 = "您的瀏覽器版本不支援canvas";
   con.appendChild(canvas);
   var parent = this;
   canvas.onclick = function(){
    parent.refresh();
   }
  },/**生成驗證碼**/
  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,this.options.width,this.options.height);
 
   if(this.options.type == "blend") { //判斷驗證碼型別
    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'; //隨機生成字型大小
    ctx.fillStyle = randomColor(50,160); //隨機生成字型顏色  
    ctx.shadowOffsetX = randomNum(-3,3);
    ctx.shadowOffsetY = randomNum(-3,3);
    ctx.shadowBlur = randomNum(-3,3);
    ctx.shadowColor = "rgba(0,0.3)";
    var x = this.options.width / (size+1) * i;
    var y = this.options.height / 2;
    var deg = randomNum(-30,30);
    /**設定旋轉角度和座標原點**/
    ctx.translate(x,y);
    ctx.rotate(deg * Math.PI / 180);
    ctx.fillText(txt,0);
    /**恢復旋轉角度和座標原點**/
    ctx.rotate(-deg * Math.PI / 180);
    ctx.translate(-x,-y);
   }
   /**繪製干擾線**/
   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.height));
    ctx.stroke();
   }
   /**繪製干擾點**/
   for(var i = 0; i < this.options.width/4; i++) {
    ctx.fillStyle = randomColor(0,255);
    ctx.beginPath();
    ctx.arc(randomNum(0,this.options.height),2 * Math.PI);
    ctx.fill();
   }
  },/**驗證驗證碼**/
  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;
   }
  }
 }
 /**生成字母陣列**/
 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(",");
 }
 /**生成一個隨機數**/
 function randomNum(min,max) {
  return Math.floor(Math.random() * (max - min) + min);
 }
 /**生成一個隨機色**/
 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內容，希望對大家的學習有所幫助，也希望大家多多支援我們。