Add/remove options to/from a select list

In my past two posts I've show how to move options between select lists and reorder options in a list. Now, to round out my little series on selection list manipulation with JavaScript, I'll give simple functions to add a value or remove a value from a list.

// addSelectOption
//
// Add the single select option to the selection list with the id specified
//
function addSelectOption(selectId, value, display) {
 if (display == null) {
  display = value;
 }
    var anOption = document.createElement('option');
    anOption.value = value;
    anOption.innerHTML = display;
    document.getElementById(selectId).appendChild(anOption);
    return anOption;
}

// removeSelectOption
//
// Remove the option with the specified value from the list of options
// in the selection list with the id specified
//
function removeSelectOption(selectId, value) {
 var select = document.getElementById(selectId);
 var kids = select.childNodes; 
 var numkids = kids.length; 
 for (var i = 0; i < numkids; i++) {
      if (kids[i].value == value) {
   select.removeChild(kids[i]);
   break;
     }
    }
}