Photoshop脚本开发疑问：“cancel”是否为关键字或保留字？

Great question! Let's break down what's happening here:

The core reason #

Photoshop's ExtendScript dialog system (using the Window("dialog") class) has built-in logic for standard button text values. When you set a button's text to one of these predefined strings—like "OK", "Cancel", "Yes", or "No"—the system automatically attaches default behavior to the button:

• A button labeled "OK" will automatically close the dialog and make dlg.show() return 1
• A button labeled "Cancel" will automatically close the dialog and make dlg.show() return 2

When you change the button text to "Can", it's no longer recognized as a standard cancel button. The system doesn't apply that default close/return logic anymore, which is why the button stops working unless you add a custom onClick handler.

Is "Cancel" a reserved keyword? #

Nope—"Cancel" isn't a JavaScript or ExtendScript reserved keyword. It's just a special text string that Photoshop's dialog system watches for to trigger default button behaviors. Think of it as a convention the scripting engine uses to map common button labels to expected actions.

Example breakdown #

Your original code works because:

var button2 = group1.add ("button", undefined);
button2.text = "Cancel";

The engine sees "Cancel" and knows "this button should act as the dialog's cancel control".

After changing to "Can", you have to explicitly define the behavior:

button2.onClick = function() {
  dlg.close();
  dialogResponse = "cancel";
}

This manually replicates the default logic that the system would have provided for the "Cancel" label.

内容的提问来源于stack exchange，提问作者Ghoul Fool