function send_message () {
	$('submit_button').disabled=true;
	var myAjax = new Ajax.Request('async/send_message.php',
	  {
		method:'post',
		parameters: $('message_f').serialize(true),
		onSuccess: function(transport){
		 var result = transport.responseText.evalJSON(true);
		  if (result.success) {
			  new Effect.BlindUp($("messageform"));
			  new Effect.BlindDown($("message_success"));
		  } else {
			  $('submit_button').disabled=false;
			  alert(result.error);
		  }
		},
		onFailure: function(){ alert('Communication error...');
			$('submit_button').disabled=false;}
	  });
	return false;
}