Adobe photoshop cs 2.0 User Guide

 Scripting basics     26

Conditional statements give your scripts a way to evaluate something and then act according to the result. 
For example, you may want your script to detect the blend mode of a layer or the name or date of a history 
state.

Most conditional statements contain the word if, or the words if and then.

The following examples check whether any documents are open; if no documents are open, the scripts 
display a dialog box that contains the message “No Photoshop CS2 documents are open!”. If one or more 
documents are open, then no dialog is displayed.

tell application "Adobe Photoshop CS2"

(*create a variable named docCount to contain the document count, 
then use the count command to get the value*)
set docCount to count every document
if docCount = 0 then

display dialog "No Photoshop  CS2 documents are open!"

end if

end tell

'create a variable named docCount for the document count, open Photoshop 

Dim docCount As long
Dim appRef As New Photoshop  CS2.Application

'use the count property of the Documents collection object to count the number of 
open documents

docCount = appRef.Documents.Count
If docCount = 0 Then

Alert "No Photoshop CS2 documents are open!"

End If

//create a variable named docCount, 
//then get its value using 
//the length property of the documents (collection) object*/
var docCount = documents.length
if (docCount == 0)
{

alert("No Photoshop  CS2 documents are open!")

}

Loops are control structures that repeat a process until the script achieves a specific goal, status, or 
condition. 

The simplest loops repeat a series of script operations a set number of times. Although you’ll find more 
substantial uses for loops, the following scripts use a variable named counter to demonstrate how to 
display a dialog box that contains the number 1, then display another dialog that contains the number 2, 
and then display a third dialog that contains 3.