Show selected option id

Hi DW, I'm trying to get selected option id, the problem with my code is that it is only showing or returning the id of the first select only even if I click other options it doesn't return them.
Heres my code

var xid = $('#managsel option:selected').attr('id');
alert("The id is: " + xid);

Here is my select option code NB: The code is generated by php.

<select class="form-control select2" style="width: 100%;" id="managsel">
<option selected="selected">Select Department</option>
<option id="opa">Accountant</option>
<option id="opb">Training</option>
<option id="opc">Operations</option>
<option id="opd">IT</option>
</select>

Also note that the options id are generated dynamically and I don't know them beforehand.
Thank you.