为什么我的网站上的所有html表单都禁用了Internet Explorer自动完成功能？

<form action="/submit" method="post" autocomplete="off">
 <input type="text" name="username" />
 <input type="password" name="password" />
 <input type="submit" value="Submit" />
</form>

document.addEventListener('DOMContentLoaded', function() {
  var forms = document.getElementsByTagName('form');
  for (var i = 0; i< forms.length; i++) {
    forms[i].setAttribute('autocomplete', 'off');
  }
});

X-UA-Compatible: IE=edge