In ASP.NET 2.0 masterpages are introduced to develop the
websites with standardized or consistent design across all pages.
The introduction of masterpages has embarked a new concept
called Url Rebasing in ASP.NET 2.0. This article mainly
explains what is Url Rebasing and its connection with
masterpages. This article also clarifies what is purpose of Url
Rebasing and reason for its emerging and also lists some interesting
points about Url Rebasing.
Purpose
Let’s say we have an image control with relative path on the
masterpage html, and Masterpage is in one folder and the content page is in
different folder. The relative image path given in the masterpage html markup
points to the wrong location and the image is not rendered. To avoid these
sorts of problems Asp.Net rebases relative urls known as Url
Rebasing.