Error: Permission denied to access property "document"
<p>I have a HTML Document which contains an <code>iframe</code>. Whenever I try to access or modify this <code>iframe</code> with JS I get <code>Error: Permission denied to access property "document"</code>.</p>

<p>I am using <code>frame.contentWindow.document.body.innerHTML</code> or <code>frame.contentWindow.document.body.onload</code> or similar such attributes to access or modify the <code>iframe</code>. (In the given code the <code>iframe</code> is referred to as <code>frame</code>.)</p>

<p>For the web-app I am developing, access to these attributes are necessary and I can't do without these (or similar alternatives).</p>