The heitml Libraries

heitml provides you with a number of Library Files that help you get your work done. This page presents an overview of the purpose of each Library. Subsequent pages in this section give more detailed information, along with explanations and examples of all the Tags.

The heitml libraries are organized as follows:

• Basic Libraries There are three Libraries dealing with session mode. Most important is the Session Library, which provides session variables. The Session Field Library displays and updates data entered into forms. The Session Trace Library maintains a list of all pages visited.

These libraries are called Basic Libraries because they provide important basic services which are used by the Component Libraries discussed in the following section. Though simple in concept, the Session Libraries form the cornerstone of heitml Web Pages, and you will no doubt come to depend on them anytime you create a suite of pages that need to share data or otherwise work in concert with one another.


• Component Libraries address specific application problems such as Database search and update, how to send mail from within a page, adding counters to pages, and creating heirarchical pages and menus in outline format. Though heitml is a full-featured programming language, Component Libraries make it possible to create complex applications simply by specifying pre-developed Tags that know how to handle the work you had in mind. Although it is possible to use a few of the Component Libraries in stand-alone fashion, most of them are designed to draw upon services provided by the Basic Libraries described above. If your Web Page design methodology centers around the simple concepts presented in the Basic Libraries, you can be sure that the Component Libraries will be ready to serve you when you need them.

• Helper Libraries provide low-level Tags for a wide range of tasks such as string manipulation, mathematical calculations, Date/Time operations, and other HTML-related extensions. These Libraries can be used in stand-alone fashion, as they do not depend on the services of any other Library.

Library Structure

Basic Libraries:

Session and SessionField libraries handle User Sessions. They contain many useful Tags that help you keep track of User input as he wanders about your Site or within your specialized applications.

Component Libraries:

dba - Database Browsing and Modification Applications The dba Component Library can be used to build database browsing and modification applications simply by defining the appropriate form layouts. dba applications employ special Tags that act as scrolling commands, allowing you to browse backwards and forwards through a database. These Tags and others in the dba Library perform consistency checks with various field formats, redisplay User input, and take care of many common operations that would otherwise require much programming on your part.

dbs - Relation Scroller With the dbs Component Library, the result of SQL Queries can be displayed in scrollable fashion. The Scroller works best when used in conjunction with Query Forms.

dbq - Database Query Forms The dbq Component Library interprets User input to a form and generates SQL Queries automatically. No need for you or the visitors to your Web Site to learn anything about SQL. These heitml pre-developed Tags allow you to work at a very high level, shielding you from the often trivial and mundane tasks that normally take up so much time when developing Web Pages that work with information stored in Databases.

mailform - Easily Creates Powerful Mailforms In addition to the usual CGI mailforms, heitml mailforms can produce emails from a User-defined text, send them to the intended recipients, display a preview, and take care of many tasks normally associated with the production of email-based newsletters, product announcements, press releases, etc. In short, heitml mailform Tags make it possible for your Secretary or Marketing Manager to perform tasks that would otherwise have required the talents of an experienced CGI programmer.

outline - Web Site Outline The Web Site Outline Library structures your Web Site in an hierarchical manner. It produces Menus that automatically expand and contract to display sub-Menu Items (as demonstrated here on our very own heitml Web Site). It produces a Table of Contents for your complete Web Site that can be printed on a single page. It also takes care of all your links (next, previous, and up). With the Web Site Outline Library, all you need do is define the structure of the Web Site in a single place. Everything else works automatically.

Helper Libraries

Date/Time, Math, and String Libraries contain many useful functions. All are designed to anticipate your needs and save you the time it would take to develop similar tools of your own. With heitml, you'll find that you can often design and develop complex Web Applications simply by using the pre-developed Tags in these and other Libraries.

Flexibility

All Libraries and Components are written in heitml and are included in Source Code.