Ungrouping an imported pdf into Illustrator

Use this script:

function releaseAllClippingMasks(doc) {
    var items = doc.pageItems;
    for (var i = items.length - 1; i >= 0; i--) {
        var item = items[i];
        if (item.typename === "GroupItem" && item.clipped) {
            try {
                item.clipped = false;
                for (var j = item.pageItems.length - 1; j >= 0; j--) {
                    item.pageItems[j].move(item, ElementPlacement.PLACEATEND);
                }
            } catch (e) {
                $.writeln("Error releasing clipping mask: " + e);
            }
        }
    }
}

function ungroupAll(doc) {
    var changed = true;
    while (changed) {
        changed = false;
        var items = doc.pageItems;
        for (var i = items.length - 1; i >= 0; i--) {
            var item = items[i];
            if (item.typename === "GroupItem") {
                try {
                    for (var j = item.pageItems.length - 1; j >= 0; j--) {
                        item.pageItems[j].move(item.parent, ElementPlacement.PLACEATEND);
                    }
                    item.remove();
                    changed = true;
                } catch (e) {
                    $.writeln("Error ungrouping: " + e);
                }
            }
        }
    }
}

if (app.documents.length > 0) {
    var doc = app.activeDocument;
    app.executeMenuCommand('unlockAll');
    app.executeMenuCommand('selectall');
    releaseAllClippingMasks(doc);
    ungroupAll(doc);
    alert("All clipping masks released and all groups ungrouped.");
} else {
    alert("No document open.");
}