Embedded Server Pages™

You can easily create new ESP functions that you can invoke from the JavaScript in your ESP page. See the Extending ESP section of the Programmer's Guide for more details.

Embedded Server Pages (ESP) is a collection of technologies developed by Embedthis and  a community of developers to provide an embeddable, standards-based, dynamic web page creation environment. Similar in its ultimate goal to PHP, Active Server Pages (ASP) and Java Server Pages (JSP), Embedded Server Pages enables the easy creation of dynamic web pages for embedded systems by embedding a powerful, standard scripting language into HTML pages.

The ESP documentation includes sections on:

• How ESP Works
• Standard Environment
• Creating Dynamic Web Pages
• Creating Forms
• Session State
• File Upload
• Programming Reference

Essentail Glue

ESP is a powerful and compact environment. It has a very small memory footprint ~50K (about 20 time smaller than PHP) and requires minimal CPU resources to execute. It is not intended to be a complete programming language like PHP, but rather to effectively provide the glue between the web and your application. Embedded applications need to be able to create powerful web applications using the minimum system resources possible. They do not need another complete programming environment, but rather an interface between HTML web pages and the core logic and data of an embedded application or system. ESP was designed to fill this role.

Embedded JavaScript

Embedded Server Pages provides a simple and convenient way to access dynamic data and script the generation of HTML. It utilizes the standard JavaScript language for server-side scripting inside ESP web pages. Best know as the de-facto scripting language in most browsers, JavaScript is ideal for server-side scripting in embedded systems due to its small memory footprint and well understood and proven language.

ESP uses JavaScript to provide a close binding between your application logic and the web page to be displayed. You can "publish" C functions as JavaScript functions with a single line of code so that your C code will be seamlessly invoked whenever the JavaScript function is called in the Web Page. 

Web Form Post-Back

ESP also allows the use of Post-Back where a single ESP page can operate as both the displayed HTML form that prompts for user input and also as the script that processes and accepts the user input. Post-Back is a very natural methodology that facilitates the placement of your application logic in one place (one web page).

Embedded Server Pages 2.0

Embedded Server Pages 2.0 represents a large enhancement over ESP 1.0. The foundation JavaScript language has been enhanced and the ESP parser has been rewritten.

Embedded JavaScript now has new features such as objects, arrays, functions and floating point. See Using Embedded JavaScript for further details. ESP leverages this to provide scriptable access to request details, sessions, cookies and uploaded files.