Hi all,
This javascript show a drop down list with counties and after selecting a country show the state.
1.There is problem because I use it into a form and the second field (field4) submit a blank value.
2.In first drop down list is possible to have a default country, can make it to have the same thing for the second dropdown list?

<script type="text/javascript" language="javascript">
var postState = '';
var postCountry = '';

var state = '\
US:NY:New York|\
US:LA:Los Angelos|\
US:CO:Colorado|\
UK:LO:London|\
UK:LI:Liverpool|\
';
var country = '\
US:United State|\
UK:United Kingdom|\
';
function TrimString(sInString) {
  if ( sInString ) {
    sInString = sInString.replace( /^\s+/g, "" );// strip leading
    return sInString.replace( /\s+$/g, "" );// strip trailing
  }
}
// Populates the country selected with the counties from the country list
function populateCountry(defaultCountry) {
  if ( postCountry != '' ) {
    defaultCountry = postCountry;
  }
  var countryLineArray = country.split('|');  // Split into lines
  var selObj = document.getElementById('countrySelect');
  selObj.options[0] = new Option('Select Country','');
  selObj.selectedIndex = 0;
  for (var loop = 0; loop < countryLineArray.length; loop++) {
    lineArray = countryLineArray[loop].split(':');
    countryCode  = TrimString(lineArray[0]);
    countryName  = TrimString(lineArray[1]);
    if ( countryCode != '' ) {
      selObj.options[loop + 1] = new Option(countryName, countryCode);
    }
    if ( defaultCountry == countryCode ) {
      selObj.selectedIndex = loop + 1;
    }
  }
}
function populateState() {
  var selObj = document.getElementById('stateSelect');
  var foundState = false;
  // Empty options just in case new drop down is shorter
  if ( selObj.type == 'select-one' ) {
    for (var i = 0; i < selObj.options.length; i++) {
      selObj.options[i] = null;
    }
    selObj.options.length=null;
    selObj.options[0] = new Option('Select State','');
    selObj.selectedIndex = 0;
  }
  // Populate the drop down with states from the selected country
  var stateLineArray = state.split("|");  // Split into lines
  var optionCntr = 1;
  for (var loop = 0; loop < stateLineArray.length; loop++) {
    lineArray = stateLineArray[loop].split(":");
    countryCode  = TrimString(lineArray[0]);
    stateCode    = TrimString(lineArray[1]);
    stateName    = TrimString(lineArray[2]);
  if (document.getElementById('countrySelect').value == countryCode && countryCode != '' ) {
    // If it's a input element, change it to a select
      if ( selObj.type == 'text' ) {
        parentObj = document.getElementById('stateSelect').parentNode;
        parentObj.removeChild(selObj);
        var inputSel = document.createElement("SELECT");
        inputSel.setAttribute("name","state");
        inputSel.setAttribute("id","stateSelect");
        parentObj.appendChild(inputSel) ;
        selObj = document.getElementById('stateSelect');
        selObj.options[0] = new Option('Select State','');
        selObj.selectedIndex = 0;
      }
      if ( stateCode != '' ) {
        selObj.options[optionCntr] = new Option(stateName, stateCode);
      }
      // See if it's selected from a previous post
      if ( stateCode == postState && countryCode == postCountry ) {
        selObj.selectedIndex = optionCntr;
      }
      foundState = true;
      optionCntr++
    }
  }
  // If the country has no states, change the select to a text box
  if ( ! foundState ) {
    parentObj = document.getElementById('stateSelect').parentNode;
    parentObj.removeChild(selObj);
  // Create the Input Field
    var inputEl = document.createElement("INPUT");
    inputEl.setAttribute("id", "stateSelect");
    inputEl.setAttribute("type", "text");
    inputEl.setAttribute("name", "state");
    inputEl.setAttribute("size", 20);
    inputEl.setAttribute("value", postState);
    parentObj.appendChild(inputEl) ;
  }
}
function initCountry(country) {
  populateCountry(country);
  populateState();
}
</script>
HTML

<select id='countrySelect' name='field3' onchange='populateState()'>
        </select>
           <select id='stateSelect' name='field4'>
        </select>
        <script type="text/javascript">initCountry('US'); </script>

set selectedIndex to the default selection

what do you mean?
Sorry, but I'm not so familiar with javascript...

you already do exactly what you need to do in the first one.

    if ( defaultCountry == countryCode ) {
      selObj.selectedIndex = loop + 1;
    }

Ok thanx chrishirst.
Now I solve to define default state but can't submit the values .
How I can define value='' for each option??

If you have no idea how this works, who wrote the original code? and do we get a link to the page that is [not] working?

I got it here but now I solve it.
Thnx for your attention.