JS禁用selectOneMenu primefaces

Question

Js档案：

$(document).on('change', '#DoctorsCreateForm\\:crm', function () {
    hideUfCrm(this, $('#DoctorsCreateForm\\:ufCrm'));
});

function hideUfCrm(crm, uf) {
    uf.disabled = crm.value === '' ? true : false;
}

XTHML页面：

<p:inputText id="crm" value="#{doctorsController.selected.crm}" title="#{bundle.CreateDoctorsTitle_crm}" required="true" requiredMessage="#{bundle.CreateDoctorsRequiredMessage_crm}"  maxlength="7" >
    <f:attribute name="uf" value="#{uf}" />
    <f:validator validatorId="crmValidator" />
</p:inputText>
<p:outputLabel value="#{bundle.CreateDoctorsLabel_ufCrm}" for="ufCrm" />
<p:selectOneMenu id="ufCrm" disabled="true"
                 value="#{doctorsController.selected.ufCrm}" required="true" requiredMessage="#{bundle.CreateDoctorsRequiredMessage_type}" binding="#{uf}" >
    <f:selectItem itemLabel="Select One" itemValue="#{null}" noSelectionOption="true" />
    <f:selectItems value="#{doctorsController.states}" var="state" itemLabel="#{state}"
                   itemValue="#{state}" />
</p:selectOneMenu>

我正在尝试禁用selectOneMenu，只有在（#crm）inputText上没有文字时，我做错了什么？