Monday, July 4, 2011

VBScript Procedures



VBScript has two kinds procedures:
  • Sub procedure
  • Function procedure

VBScript Sub Procedures

A Sub procedure:
  • is a series of statements, enclosed by the Sub and End Sub statements
  • can perform actions, but does not return a value
  • can take arguments
  • without arguments, it must include an empty set of parentheses ()
Sub mysub()
  some statements
End Sub
or
Sub mysub(argument1,argument2)
  some statements
End Sub

Example (IE Only)

Sub mysub()
  alert("Hello World")
End Sub

VBScript Function Procedures

A Function procedure:
  • is a series of statements, enclosed by the Function and End Function statements
  • can perform actions and can return a value
  • can take arguments that are passed to it by a calling procedure
  • without arguments, must include an empty set of parentheses ()
  • returns a value by assigning a value to its name
Function myfunction()
  some statements
  myfunction=some value
End Function
or
Function myfunction(argument1,argument2)
  some statements
  myfunction=some value
End Function

Example (IE Only)

function myfunction()
  myfunction=Date()
end function

How to Call a Procedure

There are different ways to call a procedure. You can call it from within another procedure, on an event, or call it within a script.

Example (IE Only)

Call a procedure when the user clicks on a button:
<body>
<button onclick="myfunction()">Click me</button>
</body>

Procedures can be used to get a variable value:
carname=findname()
Here you call a Function called "findname", the Function returns a value that will be stored in the variable "carname".
Function procedures can calculate the sum of two arguments:

Example (IE Only)

Function myfunction(a,b)
myfunction=a+b
End Function

document.write(myfunction(5,9))

The function "myfunction" will return the sum of argument "a" and argument "b". In this case 14.
When you call a procedure you can use the Call statement, like this:
Call MyProc(argument)
Or, you can omit the Call statement, like this:
MyProc argument

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