Is "cancel" a keyword or reserved word in Photoshop?

[Ghoul Fool]

Is "cancel" a keyword or reserved word?

My simple dialog box:

var dlg = new Window("dialog"); 
    dlg.text = "Proceed?"; 
    dlg.preferredSize.width = 160; 

// GROUP1
// ======
var group1 = dlg.add("group", undefined, {name: "group1"}); 
    group1.preferredSize.width = 160; 

// add buttons
var button1 = group1.add ("button", undefined);
    button1.text = "OK";
var button2 = group1.add ("button", undefined);
    button2.text = "Cancel";


var myReturn = dlg.show();

if (myReturn == 1)
{
   // code here
}

Works fine. All is well. However replace the string "Cancel" with "Can" and the button no longer functions.

You need to add extra code in order to regain functionality.

button2.onClick = function()
{
  // alert("Byas!");
  dlg.close();
  dialogResponse = "cancel";
}

So, what's going on, is "cancel" a keyword?

[Stephen_A_Marsh · Accepted solution]

Yes, in ScriptUI – OK and Cancel are "self-defined":

From the Bible "Beginning ScriptUI", by Peter Kahrel, page 15:

---

Responding to button presses

The behaviour of buttons other than OK and Cancel must be coded explicitely.

You do this with a so-called callback, in this case onClick. Here is an example:

---

var w = new Window ("dialog");
var e = w.add ("edittext", undefined, "Abcdefg");
var convert_button = w.add ("button", undefined, "Convert to upper case");
w.add ("button", undefined, "OK");
convert_button.onClick = function () {e.text = e.text.toUpperCase();}
w.show ();

Clicking Convert to upper case converts the text in the edit field to upper

case. This is a simple example, but the functions called by onClick can be of any

complexity. (There are several other types of callback, which we will deal with

later.)

Callbacks such as onClick can be combined with other callbacks in one

statement. The following script displays a small panel that we can use to check

the status of the state of the No break attribute.

---

[Ghoul Fool]

Any other "self-defined" or Photoshop only reserved words that may have eluded me?

[Stephen_A_Marsh]

I don't know, I avoid ScriptUI as much as possible!

As for JavaScript/Extendscript, there are of course case sensitive reserved words such as var or function etc.

https://www.w3schools.com/js/js_reserved.asp