'''
    var enabled;

    try {
        enabled = components.manager.QueryInterface(Ci.nsIServiceManager)
                    .isServiceInstantiatedByContractID(
                    "@mozilla.org/accessibilityService;1",
                    Ci.nsISupports);
    } catch (ex) {
        enabled = 'exeption';//false;
    }
    return enabled;
'''