Webpages and Master pages
The majority of your webpages will look very similar, and have some shared content (such as titles, logos etc). One way you could build your website is to make one page, and then keep copying it for each additional page you want and change the bits that should be different.
That's how a large number of existing websites are built, however, if you decide to change something, such as the logo, the titles, or the colour theme, you will find yourself making the same changes to all of the pages.
You may think that changing the styles and themes is something you'll rarely do, but very often in website construction, things evolve during the construction and the templates needs to change.
In order to overcome this issue, we use a '.master' page.
Master pages, (which must have the filename of '.master.mhtm') are a special type of page. They are hidden pages (hence the '.' prefix) and are never directly displayed.
They usually have a blank body, and just contain the panels that will be used on all other pages.
When an standard page is loaded, it will also load the '.master.mhtm' file from the same folder.
The standard page will render normally, but will pull in panels from the master page as well. Therefore your webpage only needs to contain the page title, and body that are unique to that page. Everything else comes from the master page.
This means that if you decide to change something in the master page, it will also take effect on all of the other pages without having to manually make the same changes over and over.
Multiple Master Pages
In a nested folder structure of webpages, all of the '.master.mhtm' pages will be loaded from all parent folders. This means that a '.master' page can inherit from other .master pages in parent folders.
Creating a Master Page
The easiest way to create a master page is through the 'Create Webpage Wizard' (see separate tutorial) and using the 'master page' option provided.
Editing a Master Page
A master page can be edited in the same way as a standard page. See separate tutorials 'Web page content' and 'Webpage styling'.
Using the Master Page in a standard page
By default, a standard page inherits everything from a master page. This is done by inserting a special type of panel, 'Inherit' in to each area.
The 'Inherit' panel can be removed if it is not needed.
Any styles on the master page are also applied, but are done before the page itself. So the page can potentially override any styles the master page has.