javascript - How to get a data-id attribute with jQuery

Question

I'm trying to get department's id value. I mean I need to get the departmentID from the element.

This function is getting the input value of elements having departmentName as a class.

this.$el.find(".departmentName").val()

example jSON

{
  "departmentID": 1,
  "departmentName": "BT"
},

My code from a BackboneJS view callback

saveEvent:function(e){
  this.$el.find(".departmentName").val(); // getting "BT"
  this.$el.find(".departmentName").attr("departmentID");//this is not working

  this.render();
},

template

<th>
    <span>{{user.department.departmentName}}</span>
    <input data-placement="top" 
           data-id="{{user.department.departmentID}}" 
           title="Bo? ge?ilemez!" 
           class="form-control text-center departmentName" 
           type='text'
           style='display: none;' 
           value='{{user.department.departmentName}}'/>
</th>

Answer 1

Use

this.$el.find(".departmentName").data("id");