How to check a checkbox jquery

I am trying to use jquery to check my checkbox:

<div class="checkbox">
  <label><input type="checkbox" value="" id="restricted_access">Restricted Access?</label>
</div>

My js:

$('#restricted_access').attr('checked', true);

But this just returns

[<input type=​"checkbox" value id=​"restricted_access" checked=​"checked">​]

Can someone help?

Thanks in advance!