实例：Canvas图片滑块拖动验证码
技术栈：HTML+CSS+JS
效果：
源码：
【HTML】
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no">
<title>Canvas图片滑块拖动验证码</title>
<link rel="stylesheet" href="181.css">
</head>
<body>
<div class="container">
<div id="captcha" style="position: relative">
<!-- <canvas width="310" height="155"></canvas>
<div class="r
