Now we will right a simple script to test we have the settings correct. Type the code shown below into your editor:

alert("Hello World")

What this simple command will do is to bring up an alert box saying ‘Hello World’; we will use alert boxes throughout this tutorial in order to test parts of our script. By putting the quote marks in we are indicating that this is a string which is just a word.

Now run your script, If you are using a regular text editor like notepad then the easiest way to run your script is to save the file as ‘myscript.jsx’ then open Photoshop and go file>scripts>browse then select your script. If you are using ESTK then just hit the play button in the top right of the document window. Automatically you should see your alert box pop up. Before testing your scripts close any document that is open in Photoshop.

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Step 2

Delete the alert code you had in the editor as we were only using it to test the settings. There are two settings we want to apply every time we run our script, these are to tell Photoshop to use pixels as the default unit and not to display dialog boxes unless we tell it to. If we wanted to do this within Photoshop we would go edit>preferences>units & rulers and change the rulers value to pixels, obviously turning off dialog boxes is limited to the scripting only. The code for doing this is:

preferences.rulerUnits = Units.PIXELS; displayDialogs = DialogModes.NO

The first command is, simply telling Photoshop to access the rulerUnits within the preferences then change the units to pixels. You will notice that this is arranged in a hierarchical structure for example the rulerUnits is contained within the preferences, this is easy to visualise as Photoshop is arranged in exactly the same way.

The second command is basically telling Photoshop to change the value of displayDialogs to NO, if you wanted to have dialogs displayed while running the script then you would change the NO to YES.

Step 3:

Now we want to let the user select a file to open, for this we need to bring up an open dialog box, even though we turned dialogs off if we tell Photoshop to bring up a dialog it will do it. We then want to define a variable that references to this document then we want to duplicate the background layer. The code for doing this is: