// stores the reference to the XMLHttpRequest object 
var xmlHttp = createXmlHttpRequestObject(); 

function createXmlHttpRequestObject(){ 
var xmlHttp; 
try{ 
xmlHttp = new XMLHttpRequest(); 
} 
catch(e)
{ 
var XmlHttpVersions = new Array('MSXML2.XMLHTTP.6.0','MSXML2.XMLHTTP.5.0', 'MSXML2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0','MSXML2.XMLHTTP','Microsoft.XMLHTTP'); 
for(var i=0; i<XmlHttpVersions.length && !xmlHttp; i++){ 
    try 
        { 
    xmlHttp = new ActiveXObject(XmlHttpVersions[i]); } 
    catch (e) 
    {
    
    } 

    } 
} 
if (!xmlHttp)
 alert("Error creating the XMLHttpRequest object."); 
else 
return xmlHttp;
 }
// make asynchronous HTTP request using the XMLHttpRequest object 

function show_pic(id){
if(xmlHttp.readyState==4||xmlHttp.readyState==0) 
{ 

xmlHttp.open("GET", "/config/show_img.php?num="+id, true);
// define the method to handle server responses 
xmlHttp.onreadystatechange = handleServerResponse; 
// make the server request 
xmlHttp.send(null); 
}
}

function handleServerResponse() {
// move forward only if the transaction has completed 
if (xmlHttp.readyState == 4) { 
// status of 200 indicates the transaction completed successfully 
if (xmlHttp.status == 200) { // extract the XML retrieved from the server 
xmlResponse = xmlHttp.responseXML; // obtain the document element (the root element) of the XML structure 
xmlDocumentElement = xmlResponse.documentElement; 
// get the text message, which is in the first child of 
// the the document element 

hm = xmlDocumentElement.childNodes[0]; 
                                  
helloMessage=hm.firstChild.data;

type = xmlDocumentElement.childNodes[1]; 
                                  
type_value=type.firstChild.data;


if(type_value==1)
{// update the client display using the data received from the server 
document.getElementById("pic_main").innerHTML = helloMessage;
} 
// a HTTP status different than 200 signals an error 
else
{ alert("There was a problem accessing the server: " + xmlHttp.statusText); 
} 
} 
}
}