Variables in ASP,
Variables have a name and can contain a value. They also have a datatype. So you sometimes you can't just compare one variable with another, you have to convert them.
The name of a variable
The name of a variable must start with a letter(a-z). The rest can contain a combination of letters and numbers.The maximum length of a name can be 255 characters.
The names are names in VB-Script are case-insensitive, he doesn't make a difference between UPPERCASE and lowercase. (counter=Counter=COUNTER)
It is recommended you use clear names.
Definition of a variable
You define a variable with the instruction DIMExample:
DIM counter, length, text
The definition is not obligated in ASP. Unless you have added the instruction "
option explicit
". Then you have to declare every variable.Data types
There are no datatypes added with the definition of the variable.
Type Explanation Numeric Whole, real, and floating-points numbers
Examples:
There are 5 different sub-types:
- counter=5
- real=-3.4
- exponential=1.4E06
- integer = whole numbers between -32 768 and 32 767
- byte = whole numbers between 0 and 255
- long = whole numbers between -2 147 483 648 and 2 147 483 647
- single = floating-point numbers single precision
- double = floating-point numbers double precision
String text always placed between double quotes ("")
You can also store numbers as string, but with calculation there is a different result
Example:
text="12"+"14" result is "1214"
sum=12+14 result is 26Date Datum and time
Example:
Datum = #09/06/2000#
Time = #11.22#Boolean These variables can only have 2 values. TRUE or FALSE
Example:
found= FALSESpecial
- Empty
- This is a variable when there is no value assigned to yet.
- NULL
- Mostly used with databases and objects. Refers to variables that are empty.
- Object
- The variable hold a pointing to an object.
With the function
Typename(nameofthevariable)
you can print the datatype of the variable.
datatype=TypeName(variable)
Constants
Constants are variables that are given a value with the definition, and cannot be changed in the programs.
CONST variable=value
There are several predefined constants.
Examples:
vbLongDate, vbSundays, vbCuan.