javascript - HTML Forms with drop down items, how to remove it from in realtime for the next form? -

i have jsp page populating 3 different drop down menus.

they populated same. looking javascript way in realtime if choose 1 dropdown next 1 go dropdown list won't have option in it.

say have 3 selects "select1","select2",and "select3". add onchange event "select1":

<script language="javascript"> function select1_onchange() {     var elemselect1 = document.getelementbyid("select1");     var elemselect2 = document.getelementbyid("select2");     var elemselect3 = document.getelementbyid("select3");     var selvalue = elemselect1.options[elemselect1.selectedindex].value;     elemselect2.remove(getindexfromvalue(elemselect2,selvalue));     elemselect3.remove(getindexfromvalue(elemselect3, selvalue)); } function select2_onchange() {     var elemselect2 = document.getelementbyid("select2");     var elemselect3 = document.getelementbyid("select3");     var selvalue = elemselect2.options[elemselect2.selectedindex].value;     elemselect3.remove(getindexfromvalue(elemselect3, selvalue)); } function getindexfromvalue(objselect,strvalue) {     var ret;     (i = 0; < objselect.options.length; i++) {         if (objselect.options[i].value == strvalue) {             ret = i;         }     }     return ret; } </script> 

tags might like:

<select id="select1" name="select1" size="1" onchange="select1_onchange()>     <option value="red">red</option>     <option value="green">green</option>     <option value="blue">blue</option>     <option value="yellow">yellow</option> </select> <select id="select2" name="select2" size="1" onchange="select2_onchange()>     <option value="red">red</option>     <option value="green">green</option>     <option value="blue">blue</option>     <option value="yellow">yellow</option> </select> <select id="select3" name="select3" size="1">     <option value="red">red</option>     <option value="green">green</option>     <option value="blue">blue</option>     <option value="yellow">yellow</option> </select>