var attente_ajax = "<p>"+chargement+". "+attente+"</p>";

attente_ajax+="<img src='_gfx/attente_ajax.gif'>";

if(debug_mode)attente_ajax += "<br /><span style='color:#000;'>"+maintenance+"</span>"

if(debug_mode && firebug)console.log("ajax.js chargé");

function requete_presentation(chapo){ //mouseover
	quitter_presentation(); //au cas ou
	
	tableau = chapo.split('_');
	id = tableau[1];
	
	document.getElementById('info_ajax').style.display='block';
	document.getElementById('info_ajax').innerHTML = attente_ajax;
	
	if(typeof(xhr)=='undefined')
	{
		if (window.XMLHttpRequest)  // Mozilla, Safari, ...
		{
			xhr = new XMLHttpRequest();
			//xhr.overrideMimeType('text/xml');
		}
		else if (window.ActiveXObject)// IE
		{ 
			xhr = new ActiveXObject("Microsoft.XMLHTTP");
		} 

	}

	if(debug_mode && firebug)console.log("id de la collection: "+id);
	
	xhr.open('POST',adresse_xhr,true);
	xhr.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
	xhr.send('id_rubrique='+id);
	xhr.onreadystatechange = presentation;
}

function presentation(){ //appelée par requete_presentation()
	if(debug_mode && firebug)console.log("état de la requete: "+xhr.readyState);
	
	if (xhr.readyState == 4) 
	{
		// afficher les données
		if (xhr.status == 200) 
		{
			contenu = xhr.responseText;
			if(contenu)
			{	
				if(debug_mode && firebug) console.log("réponse ok");
				document.getElementById('info_ajax').style.display='none';
				document.getElementById('accroche').style.display='none';
				document.getElementById('apercu_collection').style.display='block';
				document.getElementById('apercu_collection').innerHTML=contenu;
				defilement(true);
				xhr.abort();
				delete xhr;
				
			}
			else
			{
				if(debug_mode && firebug) console.log("réponse !ok= "+contenu);
				quitter_presentation();
			}
			
		} 
		else
		{
			if(debug_mode && firebug) console.log("erreur lors de la reception des données.... xhr status=" + xhr.status);
			quitter_presentation();
		}

	}
	else 
	{
		document.getElementById('info_ajax').style.display='block';
		document.getElementById('info_ajax').innerHTML = attente_ajax;
	}
}

function quitter_presentation(){ //mouseout
	//interrompre la requete et détruire l'objet
	if(typeof(xhr)!='undefined')
	{
		xhr.abort();
		delete xhr;
	}
	//arreter de boucler le défilement
	defilement(false);
	//vider la div
	document.getElementById('info_ajax').style.display='none';
	document.getElementById('apercu_collection').innerHTML='';
	document.getElementById('apercu_collection').style.display='none';
	document.getElementById('accroche').style.display='block';

}