It is supposed to work like that. Basically the .load() method will parse the HTML and insert it into the div.
jQuery uses the browser's .innerHTML property to parse the retrieved document and insert it into the current document. During this process, browsers often filter elements from the document such as
<html>
,<title>
, or<head>
elements. As a result, the elements retrieved by .load() may not be exactly the same as if the document were retrieved directly by the browser.
The easiest way to fix your problem is this:
$('#divURLContent').load('page.php body');
which will load only the "body" part of page.php. In general, you should not load an entire page inside a div, but just pieces of code.
Have a look here for further reference: Jquery to load a page overrides my CSS