$(document).ready(function() {
	var options = {
     //   target:        '#output1',   // target element(s) to be updated with server response 
        beforeSubmit:  showRequest,  // pre-submit callback 
        success:       showResponse  // post-submit callback 
		} ; 
			

	$(id_form).ajaxForm(options);
	
 
});

 
function showRequest(formData, jqForm, options) 
{
   
	document.getElementById("loader").style.visibility='visible';
	
    return true; 
}
 
 
// post-submit callback 
function showResponse(responseText, statusText)  
{
	
  if (statusText=='success') { eval(responseText); 	document.getElementById("loader").style.visibility='hidden'; }
}