Wherever they appear, Visual Basic scripts are processing routines called upon by the Web page to carry out its processing activities and to produce the output results for display on the page. Visual Basic code can be physically located in the two places. Code can appear on the Web page itself; it can also appear in a separate file that is accessible from the Web page.

A script block is simply the section of the page surrounded by <script> tags in the following format. It must be enclosed within an identifiable script block,when Visual Basic code appears on a Web page,

A script block can appear anywhere on the Web page, and there can be as many script blocks as the user needed. However, a single script block is normally the sufficient one, and it commonly appears at the top of the Web page, prior to any HTML code that appears on the page. The reason for the placing the script at the top of the page is in recognition of the fact that the server runs the script first, before it takes action on any other components of the Web page.

The attribute runat="server" indicates that the enclosed script is to be run, or executed, by Web server computer prior to transmitting the page to the client computer which made the URL request for the page and the attribute also differentiates server scripts from browser scripts that also are enclosed within <script> tags.In the JavaScript language,these browser-based scripts are usually written.

Optionally, language="vb" or language="Visual Basic" can be included in the opening tag to indicate the programming language used in the script and this attribute is optional since Visual Basic is the default server language for Web page scripts.

Although the topic of subprograms and other similar containers is covered later in these tutorials and one particular subprogram can provide the wrapper for the statements introduced over the next several tutorials. The Page_Load subprogram is the one that the server first runs when the Web page is opened. Any statements can be placed inside this subprogram for immediate execution. A general script setup to run Visual Basic statements, then, is shown by the following outline.

A script block is the enclosing container for all Visual Basic statements on a page and however, most statements must be enclosed inside another programming structure in order to be executed properly. This structure is a named container that can be called upon to perform the processing given by its enclosed statements. The most common container for statements is a subprogram.

There are slight coding differences between an an external class and internal script and a Web-page script is supplied with various default language settings that must be made explicit when coding a formal Visual Basic class. These differences are pointed out later in the tutorials and when learning the Visual Basic language it is best to develop Web pages with on-page scripts to remove the complexities of constructing classes. The second location for Visual Basic code is in a separate code-behind file and this file contains only Visual Basic code packaged as a Visual Basic class. The file name is always given the extension .vb to indicate a Visual Basic program.