Unlock Master page items

Hi @Bedazzled532, well done on seeing what to change in the script to make it work—you removed the predicate that was interfering with your needs. However there is another problem: the script will crash when the selected page item doesn't exist on the page, which will happen when the selected page item is on, say, the left-hand page of the master spread, but the script is checking page 1 which is a right-hand page. I've added a try-catch that ignores pages that get this error.

And a counter is always nice so that you know that something happened!

- Mark

function main() {

    var doc = app.activeDocument;
    var sel = doc.selection[0];

    if (
        sel == undefined
        || !sel.isValid
        || !sel.hasOwnProperty('parentPage')
        || sel.parentPage.parent.constructor.name !== "MasterSpread"
    ) {
        alert("Error\rSelect exactly one item on a master page and try again.");
        return;
    }

    var masterSpread = sel.parentPage.parent,
        counter = 0;

    for (var i = 0; i < doc.pages.length; i++) {
        var page = doc.pages[i];
        if (page.appliedMaster == masterSpread) {
            try {
                sel.override(page);
                counter++;
            } catch (error) {
                // item doesn't exist on that page
            }
        }
    }

    alert('The selected item was overridden on ' + counter + ' pages.')

};

app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Override Selected Master Page Item');