VBScript Reference Manual for InduSoft Web Studio

InduSoft Web Studio VBScript Reference Manual
Variable Naming Rules & Conventions
VBScript has four primary rules for naming. These are:
1. Variable names must begin with an alpha character (a..z, A...Z) or an underscore character
2. After the first character, the variable name can contain letters, digits and underscores
3. Variable names must be less than 255 characters in length
4. The variable name must be unique in the scope in which they are declared
VBScript variable names are not case sensitive. Microsoft recommends following their naming
convention for variables, which puts attaches different prefixes to the variable name based on the data
subtype.
Variable Scope
Variables have “scope” which defines a variable’s visibility or accessibility from one procedure (or
VBScript Interface) to another, which is principally determined by where you declare the variable.
Generally, when you declare a variable within a procedure, only code within that procedure can access
or change the value of that variable. This is called local scope and is for a procedure-level variable.
If you declare a variable outside a procedure, you make it recognizable to all the procedures in your
Script. This is a Script-level variable, and it has Script-level scope. However, as previously noted,
InduSoft enforces certain restrictions on the scope of Variables and Procedures.
VBScript Constants
VBScript supports both explicit and implicit constants. Constants should never be used as variable
names.
Explicit constants are defined by the programmer. Explicit constants have a defined value which, unlike
a variable, is not allowed to change during the life of the script.
Implicit constants are pre-defined by VBScript. VBScript implicit constants usually begin with a vb
prefix. VBScript implicit constants are available to the VBScript programmer without having to define
them. Other objects, such as those used by ADO.NET, also have implicit constants predefined, usually
with different prefixes. However, the implicit constants for these objects may not be know to VBScript
and if not, will have to be defined as an explicit constant.
VBScript defines the following categories of implicit Constants:
Intrinsic Constant Category Intrinsic Constant Category
Color Constants File Attribute Constants
Comparison Constants File Input/Output Constants
Date and Time Constants MsgBox Constants
Date Format Constants MsgBox Function Constants
Days of Week Constants SpecialFolder Constants
New Years Week Constants String Constants
Error Constants Tristate Constants
VBScript Runtime Errors VarType Constants
VBScript Syntax Errors Locale ID (LCID)
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