Developing Web Applications
Developing Web Applications |
|
It’s often a good idea to collect commonly used functions into one file and to include that file in all pages requiring those functions.
The include file can contain plaintext, declare functions and subroutines with <SCRIPT> tags, or can define variables and constants. To include the file, use a server-side include directive at the top of your file. Here is an example:
<!-- #include virtual="/MyRoot/include/funclib.inc" -->
Usually, include files are named with the .inc extension. Although this differentiates the file, it may pose a security threat if you have directory browsing enabled. The .inc extension is not normally script-mapped by IIS 5.0, and most browsers don’t recognize it. Consequently, anyone who knows where to find the files can download and open them. You can prevent this from happening by either associating the .inc extension with Asp.dll in the script map (use the App Mappings tab of the Application Configuration dialog box), or by storing the include files in their own subdirectory and disallowing directory browsing as well as read access.
The entire text of the include file is incorporated into the .asp source file at the point where the include statement appears. Although there is technically no limit to the number of files you can include, each one adds to the size of the compiled .asp file—so it’s better to include only files that you know you will need.
Since all include files are processed before the script executes, you cannot dynamically decide which file to include. For the same reason, you cannot use the include directive in Global.asa.