Question

 <input id="studentnoofinst" type="text" size="20" value=""/>
<select id="studentinst" size="6">
<option value="1">First Installment</option>
<option value="2">Second Installment</option>
<option value="3">Third Installment</option>
<option value="4">Fourth Installment</option>
<option value="5">Fifth Installment</option>
<option value="6">Sixth Installment</option>
</select>

Jquery

 $("#studentnoofinst").keyup(function() { 

    //$("select option[value='fb']").prop("selected",true);
    alert("going to change");
    $leap=0;
    $leap=($('#studentnoofinst').val());
    if($leap!=''){
    for(i=$leap;i<=6;i++) {// displaying the no of installments 
        if(i!=$leap){
            $('#studentinst option[value='+i+']').remove();

 }
     }    
    }

});

Hi, as shown in the code above i am able to remove the selected row, My question is that i am not able to add the selected option back,How to add the selected row back
P.S:once if enter 4 the last 2 rows are deleted and later if enter 5 only the first 4 rows are display and the 5 row is vomitted.. but it need it

if first time the input =4

ouptut:

  <option value="1">First Installment</option>
  <option value="2">Second Installment</option>
  <option value="3">Third Installment</option>
  <option value="4">Fourth Installment</option>

if second time the input =5

ouptut:

  <option value="1">First Installment</option>
  <option value="2">Second Installment</option>
  <option value="3">Third Installment</option>
  <option value="4">Fourth Installment</option>
  <option value="5">Fifth Installment</option>//vomitted but i need this? add

Live example here: http://jsfiddle.net/PQ7GF/30/

Answer 1

EDIT – merged the changes made by soul:

you could save the options in a variable and add them back:

var list = $('#studentinst').html();
$("#studentnoofinst").keyup(function() {
    $('#studentinst').empty().append(list);
    alert("going to change");
    $leap = 0;
    $leap = ($('#studentnoofinst').val());
    if ($leap != '') {
        for (i = $leap; i <= 6; i++) { // displaying the no of installments 
            if (i != $leap) {
                $('#studentinst option[value=' + i + ']').remove();
            }
        }
    }
});

fiddle here: http://jsfiddle.net/PQ7GF/49/