Given the following HTML and JavaScript, what do I need to change to get the selected value?

<select id="col_1" name="col_1" class="columnMapping">
  <option value="">Select</option>
  <option value="1">Ignore</option>
  <option value="2">Location</option>
  <option value="3">Department</option>
  <option value="4">Role</option>
  <option value="5" selected="selected">User Name</option>
  <option value="6">First Name</option>
  <option value="7">Last Name</option>
  <option value="8">Email</option>
  <option value="9">Status</option>
  <option value="10">AltId</option>
  <option value="11">Phone Number</option>
  <option value="12">Reports To User Name</option>
  <option value="13">Reports To AltId</option>
</select>
<!-- More similar <select> elements to follow... -->

var arrSelectedVals = [];
for (var i = 0; i < $('table.dataTable select.columnMapping').length; i++) {
  arrSelectedVals.push($('table.dataTable select.columnMapping').eq(i).find(':selected').val());
}

I keep getting an array of empty strings.