var xhr = null;

function get_Xhr(){
 var xhr = null;
 if(window.XMLHttpRequest) xhr = new XMLHttpRequest();
 else if(window.ActiveXObject) xhr = new ActiveXObject("Microsoft.XMLHTTP");
 else alert("Votre navigateur ne supporte pas les objets XMLHTTPRequest...");     
 return xhr;
}

function chang_fp(){
   var xhr = get_Xhr();
   xhr.onreadystatechange  = function(){ 
     if(xhr.readyState  == 4){
       if(xhr.status  == 200){
         if(xhr.responseText!=''){
           document.getElementById('fport').innerHTML = xhr.responseText+' €';
         }
         else{
           document.getElementById('fport').innerHTML = "PROBLÈME";
         }
       }
       else 
         document.getElementById('fport').innerHTML="Error code " + xhr.status;
       }
   };
   data = 'port='+document.getElementById('port').value+'&pays='+document.getElementById('cpays').value;
   xhr.open( "POST", "utils/chang_fp.php",  true);
   xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");                  
   xhr.send(data);
}