Originariamente inviato da Xinod
codice:
function tuaFunzione(bla){
  ...
  return false; // = non vuoi inviare il form
}
...
<form onsubmit="return tuaFunzione('blablabla')">
Ok, ma così non si sposta più su http://www.yahoo.com...

codice:
<html>
<head>

  <script type="text/javascript">
 
    var xml_http_obj = false;
 
    if (window.XMLHttpRequest){
      //Firefox, safari etc
      xml_http_obj = new XMLHttpRequest();
    }else if(window.ActiveXObject){
      //Microsoft IE
      xml_http_obj = new ActiveXObject("Microsoft.XMLHTTP");
    }
 
    function get_data(url,wait_div_id){
 
      if (xml_http_obj){
 
        xml_http_obj.open("GET",url,true);
 
        xml_http_obj.onreadystatechange = function(){
 
          if (xml_http_obj.readyState == 4 && xml_http_obj.status == 200){
 	    document.getElementById(wait_div_id).style.visibility="hidden";
          }else{
	    document.getElementById(wait_div_id).style.visibility="visible";
          }
        }
 
        xml_http_obj.send(null);
      }
 
      return false;
    }
  </script>
 
  <style>
    div#wait{
      background-color:white;
      position:absolute;
      top:240px;
      left:360px;
      width:400px;
      height:50px;
      visibility:hidden;
      border: 0px;
      padding:0px;
    }
  </style>
 
</script>
</head>
 
<body id="body">
 
  <H1>Please Wait AJAX </H1>
  
  <form action="http://www.yahoo.com" method="post" onSubmit="return get_data('go_to_sleep.php','wait')">
 
  <div id="wait" >
    [img]wait.gif[/img]Please wait ...
  </div>

<input type="submit" value="Search">  
  </form>    

</body>
</html>