console 命令行工具 X clear

console

var oWrapper = document.getElementsByClassName('wrapper')[0]
var oBtn = document.getElementById('submit')



oWrapper.onscroll = function(){
if(oWrapper.scrollHeight - oWrapper.scrollTop <= oWrapper.clientHeight){
  oBtn.disabled = false
}else{
  oBtn.disabled = true
}
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>滚动条触底</title>
</head>
<body>
  
  <div class="wrapper">
    <h3>亲爱的，欢迎注册</h3>
    <p  class="info">
     亲爱的用户，请仔细阅读以下协议,如果你不仔细阅读，你就别注册
    </p>
  </div>
    <div class="register">
        <input type="checkbox" />我已阅读条例
        <button id="submit" disabled>提交</button>
    </div>   
    
</body>
</html>

.wrapper{
  width:500px;
  height:500px;
  border:1px solid #000;
  text-align: center;
  overflow:auto;
}

.info{
  height:1000px;
}

.register{
  margin-top: 20px;
  margin-left: 180px;
}