Every template-based page has regions the page author can edit and regions that can't be edited. As such, a template can contain text, images, styles, and editable regions. In this section, we'll review the components that make up a template. There are four regions in each template page that can contain text, images, page layout, and styles. These four regions are:
Editable tag attribute
The template author determines which regions are editable by including editable regions or editable parameters. An editable region is simply an unlocked area that you can modify. When basing a new page on a template, the page author can make changes only to editable regions. All other regions are locked. For this reason, a template should contain at least one editable region.
Repeating regions do just what their name implies-they repeat areas of a web page, typically tables. There are two types of repeating regions:
Repeating tables When you are designing a page, particularly using HTML tables, it is difficult to determine in advance how many table or cell elements page authors might require. Using a repeating region, you can permit a page author to simply repeat as many tables or table cells as needed. The number of rows might be different from page to page, which doesn't matter to the template. A repeating region repeats sections, but it isn't editable unless you add an editable region to the repeating region.
Repeating regions A repeating region is similar to a repeating table. However, in this case, it can be applied to almost any page element, even to a small bit of text. By default, the repeating region isn't editable. You must make the region editable.
Use optional regions for text or images that are part of the template's basic design but that may or may not appear in every page of the site. When creating the new templated-based page, the page author controls whether the page displays the optional content.
Each new template-based page isn't restricted to all the template's design elements. Using an editable tag attribute, you can unlock a template tag, allowing the page author to edit that tag in the new page. For instance, the basic design might call for a graphic that should normally be left-aligned, but you as template author anticipate that on some pages this placement will need to be adjusted. Because the graphic needs to appear on every page, it must be a repeating region, but by making the align attribute an editable tag, you allow the page author to align the graphic as needed. You'll learn more in "Using Editable Tag Attributes" later in this chapter.