ASP Best Practices

Scoping Variables

Using Page Scope for Best Performance

Local variables reside within functions and subroutines. Give page scope (also called local scope) to variables unless you have a compelling reason to use a broader scope. For example, you might want to assign session scope to a variable that is used in more than one script in a user session. Local variables are compiled into table entries. At run time, references to local variables are resolved with fast-executing table lookups, giving local variables faster performance than global variables.

Using Global Variables Sparingly and Efficiently

Global variables are resolved at run time, and execute much more slowly than local variables. An undeclared global variable is the slowest, requiring a search of the entire variable list the first time it is used. When you need to give global scope to variables, declare them using the Dim statement before using them. This saves valuable time on first use by eliminating a search of the entire variable list.

Avoiding the Use of Public Variables

Do not use variables defined as Public. The Public keyword is under review to determine future use. Use Dim instead.