how to read a text box value using jquery

Question

i am using a select control while showing all the availble items from the database,but when i want to add a new record i am converting the select in a text box.After converting the text box i am unable to read the value of it 

 

select declration 

<tr>

<td style="width: 10em; border: 0 !important;"><span style="color: red">*</span>Board ID</td>

<td class="form-group form-group-sm" style="border: 0 !important;">

<select class="form-control" id="cmbBoardID" name="cmbBoardID" style="width: 6.6em; padding-left: 1px;">

</select></td>

</tr>

 converting to text box

function Add() {

$('#cmbBoardID').replaceWith($("<input/>", { type: "text" }));

 }

 

  reading the value

 

Var Boardid = $('#cmbBoardID').val(); 

 

 

getting undefined while reading value as above.Any suggestions would be helpful .

Thanxs in advance