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本篇內容主要講解“JS如何實現圖片驗證碼功能”，感興趣的朋友不妨來看看。本文介紹的方法操作簡單快捷，實用性強。下面就讓小編來帶大家學習“JS如何實現圖片驗證碼功能”吧!
1. html代碼
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script src="<%=request.getContextPath()%>/js/gVerify.js"></script>
<style type="text/css">
body, html {
width: 100%;
text-align: center;
}
#picyzm {
width: 100px;
height: 40px;
display: inline-block;
margin: 0 30px;
}
#verifyCodeDemo {
width: 100%;
display: flex;
margin-top: 200px;
justify-content: center;
}
#btn {
margin: 30px auto;
background-color: blue;
color: #fff;
border-radius: 5px;
border: 0;
width: 100px;
height: 40px;
}
</style>
</head>
<body>
<div id="verifyCodeDemo">
<input type="text" id="code_input" placeholder="在這個框里輸入驗證碼">
<p id="picyzm"></p>
</div>
<input type="button" value="驗證" id="btn">
<script type="text/javascript">
//初始化驗證碼
var verifyCode = new GVerify({
id : "picyzm",
type : "blend"
});
//點擊按鈕驗證
var code = document.getElementById("code_input");
var btn = document.getElementById("btn");
btn.onclick = function() {
var res = verifyCode.validate(code.value);
if (res) {
alert("驗證通過");
} else {
alert("驗證碼錯誤");
}
}
</script>
</body>
</html>2. 引入gVerify.js
!(function(window, document) {
function GVerify(options) { // 創建一個圖形驗證碼對象，接收options對象為參數
this.options = { // 默認options參數值
id: "", // 容器Id
canvasId: "verifyCanvas", // canvas的ID
width: "100", // 默認canvas寬度
height: "30", // 默認canvas高度
type: "blend", // 圖形驗證碼默認類型blend:數字字母混合類型、number:純數字、letter:純字母
code: ""
}
if(Object.prototype.toString.call(options) == "[object Object]"){// 判斷傳入參數類型
for(var i in options) { // 根據傳入的參數，修改默認參數值
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持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, 0, this.options.width, this.options.height);
if(this.options.type == "blend") { // 判斷驗證碼類型
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'; // 隨機生成字體大小
ctx.fillStyle = randomColor(50, 160); // 隨機生成字體顏色
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);
/** 設置旋轉角度和坐標原點* */
ctx.translate(x, y);
ctx.rotate(deg * Math.PI / 180);
ctx.fillText(txt, 0, 0);
/** 恢復旋轉角度和坐標原點* */
ctx.rotate(-deg * Math.PI / 180);
ctx.translate(-x, -y);
}
/** 繪制干擾線* */
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.width), randomNum(0, this.options.height));
ctx.stroke();
}
/** 繪制干擾點* */
for(var i = 0; i < this.options.width/4; i++) {
ctx.fillStyle = randomColor(0, 255);
ctx.beginPath();
ctx.arc(randomNum(0, this.options.width), randomNum(0, this.options.height), 1, 0, 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{
return false;
}
}
}
/** 生成字母數組* */
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);3. 效果圖
到此，相信大家對“JS如何實現圖片驗證碼功能”有了更深的了解，不妨來實際操作一番吧！這里是億速云網站，更多相關內容可以進入相關頻道進行查詢，關注我們，繼續學習！
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