window.parent.Xrm.Page.ui.tabs.get(2);

var tab = window.parent.Xrm.Page.ui.tabs.get(2);

tab.sections.forEach(function (section, sectionIndex)
{
    section.controls.forEach(function (control, controlIndex)
    {
        switch (control.getControlType())
        {
            case "standard":
            case "lookup":
            case "optionset":
                var attribute = control.getAttribute();

                if (attribute != null)
                {
                    alert(attribute.getName());
                }
                break;
        }
    });
});