Get external href attribute

Get external href attribute

When triggered, I wish to change the href attribute of a link in the current html file to be the same as the href of a link in another html file. So for example:

Before trigger

Some.html (current page)
<a ID="something" href="somewhere.html"></a>

SomeOther.html
<a ID="somethingelse" href="somewhereelse.html></a>

After trigger
Some.html
<a ID="something" href="somewhereelse.html"></a>

SomeOther.html
<a ID="somethingelse" href="somewhereelse.html></a>

I've tried

$('#something').attr('href', somewhereelse.html + ' #somethingelse'.attr('href'));

Amongst many other things, but while I can load the content of a div in another page, and get the href of an element on the current page, I can't work out how to get the href of an element on another page.

Any help is much appreciated:)