function createXmlHttpRequestObject(){
    var req = false;

    if(window.XMLHttpRequest && !(window.ActiveXObject)) {
        try {req = new XMLHttpRequest();}
        catch(e) {req = false;}
        }
    else if(window.ActiveXObject) {
       	try {req = new ActiveXObject("Msxml2.XMLHTTP");}
      	catch(e) {
      	    try {req = new ActiveXObject("Microsoft.XMLHTTP");}
        	catch(e) {req = false;}
	    }
        }
	return req;
}


var request;  //Esta variable ha de ser global.

function callWS(url, responseHandler, parameters) {
    var strParameters = "";
    request.onreadystatechange = responseHandler;
    request.open("POST", url, true);

    if(parameters != null && parameters.length != 0) {
        request.setRequestHeader('Content-Type','application/x-www-form-urlencoded');

        for(var i = 0; i < parameters.length; i++) {
            var p = parameters[i];
            if(strParameters != "") strParameters += "&";
            strParameters += p[0] + "=" + p[1];
        }
    }
   request.send(strParameters);
}


function getResponse(){
    var res = '';
    for (var i=0; (i < request.responseXML.documentElement.childNodes.length); i++) {
        if (request.responseXML.documentElement.childNodes.item(i))
            {res = res + request.responseXML.documentElement.childNodes.item(i).nodeValue;}
        }
    res = res.replace(/</g, "<").replace(/>/g, ">");
    return res;
}

function getResponseDatos() {
    if(request.readyState == 4 && request.status == 200) {
        document.getElementById('divDatos').innerHTML=getResponse();
    }
}

//Peticion sin parametros:
function getDatos(){

		request = createXmlHttpRequestObject();
		callWS("addimg.asp", getResponseDatos, null);
		
}



//Petición con parámetros:
function getDatosConParam(idImagen){
 
        var parameters = new Array();
        parameters[0] = new Array("im", idImagen);
        parameters[1] = new Array("acc", "addimg");
        request = createXmlHttpRequestObject();
        callWS("addimg.asp", getResponseDatosConParam, parameters);
        
}
function getResponseDatosConParam() {
    if(request.readyState == 4 && request.status == 200) {
        document.getElementById('divDatos').innerHTML=getResponse();
    }
}

  

function Actualizacheckbox(idUsuario){

        var parameters = new Array();
        parameters[0] = new Array("iu", idUsuario);
        parameters[1] = new Array("acc", "lista");
        request = createXmlHttpRequestObject();
        callWS("addimg.asp", ResponseActualiza, parameters);
        
}

function ResponseActualiza() {

    if(request.readyState == 4 && request.status == 200) {
		var res = '';

		for (var i=0; (i < request.responseXML.documentElement.childNodes.length); i++) {
	//		alert( request.responseXML.documentElement.childNodes(i).firstChild.text);
				res = request.responseXML.documentElement.childNodes(i).childNodes(0).firstChild.text;
			res = res.replace(/</g, "<").replace(/>/g, ">");
			document.getElementById('cb'+res).checked=true;
			        document.getElementById('divDatos').innerHTML+=res;
		}
	}
    return true;   
}