<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>随机验证码（带干扰线）</title>
</head>
<style>
.codeVesselBox {
width: 120px;
height: 30px;
margin-bottom: 4px;
}
</style>
<body>
<div>
<div class="codeVesselBox" id="vCodeImg"></div>
<div class="iptBox">
<input id="id" type="text">
<button onclick="threeFn()">提交</button>
</div>
</div>
</body>
<script>
(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: "", //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(100, 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 / 1.2, this.options.height) +
'px SimHei'; //随机生成字体大小
ctx.fillStyle = randomColor(1, 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 / 6; i++) {
//this.options.width / 6，除以的值越大，点越少
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();
// toLowerCase() 方法用于把字符串转换为小写。
var v_code = this.options.code.toLowerCase();
console.log(code);
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);
// 调用GVerifty
var verifyCode = new GVerify("vCodeImg");
console.log(verifyCode.options.code);
function threeFn() {
var a = document.getElementById('id').value;
if (a != verifyCode.options.code) {
alert("验证码错误")
console.log(a, "验证码的值...");
} else {
alert("验证码正确")
console.log(a, "验证码的值...");
}
}
</script>
</html>
转载：原文更详细
原文链接：https://blog.csdn.net/Shids_/article/details/126161653?spm=1001.2014.3001.5502