I have a basic script which allows me to click on the website's background, excluding `#content`.

After upgrading jQuery to 3.1.0 version, I get this error:
`TypeError: $(...).parents(...).size is not a function`.

```
<script type="text/javascript">
  $(function() {
    $("#background").click(function(e) {
      if (e.target.id == "wrapper" || $(e.target).parents("#wrapper").size()) 
      {
        // do nothing
      } 
      else
      {
        window.open('http://example.com');
      }
    });
  })
</script>`

```

I don't know how to fix it. jQuery is loaded properly. Please help.