function loadCities()
{
    while(document.getElementById('cmb_city').length-1>0)
         document.getElementById('cmb_city').options[document.getElementById('cmb_city').length - 1] = null;
    var state_id = document.getElementById('cmb_state').value;
    if(state_id=='--Select--')
    {
        return false;
    }
     document.getElementById("cmb_city").disabled = true;
    var success	= function(t){
    var mysmstags = t.responseXML.getElementsByTagName('cities_160by2');
    var objtable = document.getElementById('cmb_city');
   for(var m = 0; m < mysmstags.length; m++)
    {        
        var city_name = mysmstags[m].getElementsByTagName('city_name')[0].firstChild.nodeValue; 
        var city_id = mysmstags[m].getElementsByTagName('city_id')[0].firstChild.nodeValue; 
         objtable.options[objtable.length] = new Option(city_name, city_id);
      }
      document.getElementById("cmb_city").disabled = false;
    }
 var failure	= function(t){
         // alert(t.responseText);
        return false;
    }
 var url = 'load_cities.aspx';
 var pars = 'state_id=' + state_id;
 var myAjax = new Ajax.Request(url, {method:'post', postBody:pars, onSuccess:success, onFailure:failure}); 
 return false;   
}