javascript function to add to pulldown menu -

okay, have pulldown menu looks this:

  <form action="" method="post" name="myform">             <select name="test_select">                 <option value="1">my val 1</option>                 <option value="3">my val 3</option>                 <option value="4">my val 4</option>             </select>             <input type="submit" value="test_button" name="test_button">         </form> 

just basic menu. how can search through , add value 2 menu function? want end looking this:

 <form action="" method="post" name="myform">                 <select name="test_select">                     <option value="1">my val 1</option>                     <option value="2">my val 2</option>                     <option value="3">my val 3</option>                     <option value="4">my val 4</option>                 </select>                 <input type="submit" value="test_button" name="test_button">             </form> 

i tried making function, show trying go this.

<script>         function additems()         {             var option = document.createelement("option");              option.text = "val 2"             option.value = 2              (var = 1; < 3; i++; ) {                 if (document.getelementsbyname.value < 2) {                     option.text = "val 2"                     option.value = 2                 }             }          }     </script> 

how make function work?

i modified code bit make work

function additems()     {       var option = document.createelement("option");        option.text = "val 2";       option.value = 2;        var select = document.getelementsbyname('test_select');       var firstgreater = null;       if (select.length > 0)       {         for(var = 0; < select[0].children.length; i++)         {           if (select[0].children[i].value > 2)           {             firstgreater = select[0].children[i];             break;           }          }         if (firstgreater != null)           select[0].insertbefore(option, firstgreater);         else           select[0].appendchild(option);       }           } 

this snippet not need addition library, can see live demo here on jsbin