JavaScript : จะเพิ่ม Attribute ของ Tag <option> โดยใช้ JavaScript

<script language="JavaScript" type="text/javascript">
<!--
var ios = 0;
var aos = 0;
function insertOldSchool(theSel, newText, newValue)
{
  if (theSel.length == 0) {
    var newOpt1 = new Option(newText, newValue);
    theSel.options[0] = newOpt1;
    theSel.selectedIndex = 0;
  } else if (theSel.selectedIndex != -1) {
    var selText = new Array();
    var selValues = new Array();
    var selIsSel = new Array();
    var newCount = -1;
    var newSelected = -1;
    var i;
    for(i=0; i<theSel.length; i++)
    {
      newCount++;
      if (newCount == theSel.selectedIndex) {
        selText[newCount] = newText;
        selValues[newCount] = newValue;
        selIsSel[newCount] = false;
        newCount++;
        newSelected = newCount;
      }
      selText[newCount] = theSel.options[i].text;
      selValues[newCount] = theSel.options[i].value;
      selIsSel[newCount] = theSel.options[i].selected;
    }
    for(i=0; i<=newCount; i++)
    {
      var newOpt = new Option(selText[i], selValues[i]);
      theSel.options[i] = newOpt;
      theSel.options[i].selected = selIsSel[i];
    }
  }
}

function appendOldSchool(theSel, newText, newValue)
{
  if (theSel.length == 0) {
    var newOpt1 = new Option(newText, newValue);
    theSel.options[0] = newOpt1;
    theSel.selectedIndex = 0;
  } else if (theSel.selectedIndex != -1) {
    var selText = new Array();
    var selValues = new Array();
    var selIsSel = new Array();
    var newCount = -1;
    var newSelected = -1;
    var i;
    for(i=0; i<theSel.length; i++)
    {
      newCount++;
      selText[newCount] = theSel.options[i].text;
      selValues[newCount] = theSel.options[i].value;
      selIsSel[newCount] = theSel.options[i].selected;
      
      if (newCount == theSel.selectedIndex) {
        newCount++;
        selText[newCount] = newText;
        selValues[newCount] = newValue;
        selIsSel[newCount] = false;
        newSelected = newCount - 1;
      }
    }
    for(i=0; i<=newCount; i++)
    {
      var newOpt = new Option(selText[i], selValues[i]);
      theSel.options[i] = newOpt;
      theSel.options[i].selected = selIsSel[i];
    }
  }
}

function removeOldSchool(theSel)
{
  var selIndex = theSel.selectedIndex;
  if (selIndex != -1) {
    for(i=theSel.length-1; i>=0; i--)
    {
      if(theSel.options[i].selected)
      {
        theSel.options[i] = null;
      }
    }
    if (theSel.length > 0) {
      theSel.selectedIndex = selIndex == 0 ? 0 : selIndex - 1;
    }
  }
}
//-->
</script>

<form>
<input type="button" value="Insert"
 onclick="ios++; insertOldSchool(this.form.selos, 'Insert' + ios, 'insert' + ios);" />
<input type="button" value="Append"
 onclick="aos++; appendOldSchool(this.form.selos, 'Append' + aos, 'append' + aos);" />
<input type="button" value="Remove"
 onclick="removeOldSchool(this.form.selos);" />
<br />
<select name="selos" size="10" multiple="multiple">
<option value="original1">Orig1</option>
<option value="original2">Orig2</option>
<option value="original2" selected="selected">Orig3</option>
<option value="original2">Orig4</option>
</select>
</form>