Adobe photoshop cs 2.0 Guia Do Utilizador

 Scripting basics     27

Set counter to 1
repeat with counter from 1 to 3

display dialog counter

end repeat

In VBScript, this type of loop is called a For-Next loop.

Dim counter As Integer
For counter = 1 to 3

Alert counter

Next

In JavaScript, this type of loop is called a for loop.

In the following script, the variable that contains the counter is named i. This represents an 
exception to the rule of thumb for good naming practices for variables. However, i is a traditional 
counter variable name and most script writers recognize its meaning, especially when i is used in a 
loop. See 

 for details on variable naming practices.

var i
for (i =1; i < 4; i=i + 1)
{

alert(i)

}

The condition in the for loop contains three statements (separated by semicolons):

●

i = 1

 — Set the value of i to 1.

●

i<4

 — If i is less than 4, execute the statement in brackets; if i is equal to or more than 4, stop and 

don’t do anything else with this loop. 

●

i=i + 1

 — After executing the statement in the brackets, add 1 to the value of i. 

The equation i=i + 1 can be abbreviated to i++.

A more complicated type of loop includes conditional logic, so that it performs a task while or until some 
condition is true. Conditional statements in a script can include the words while, until, or if — just like in 
English. 

For example, you could make the conditional statement “I’ll use scripts only if they make my life easier.” 
Another way to say this is, “I’ll use scripts only on the condition that they make my life easier.” 

Similarly, in the sentence, “I’ll write scripts only while I’m at work,” the condition is being at work. The same 
condition is worded with a slight difference in the following sentence: “I’ll write scripts only until I leave 
work.” 

➤

1. Display a “Quit?” dialog. 

The dialog contains two possible responses: an OK button and a Cancel button. 

2. When the user clicks Cancel (for “Don’t quit.”), the script displays the dialog again.