// JavaScript Document
// creates an XMLHttpRequest instance
function createXmlHttpRequestObject()
{
    // will store the reference to the XMLHttpRequest object
    var xmlHttp;
    // this should work for all browsers except IE6 and older
    try
    {
        // try to create XMLHttpRequest object
        xmlHttp = new XMLHttpRequest();
    }
    catch(e)
    {
        // assume IE6 or older
        var XmlHttpVersions = new Array('MSXML2.XMLHTTP.6.0',
                'MSXML2.XMLHTTP.5.0',
                'MSXML2.XMLHTTP.4.0',
                'MSXML2.XMLHTTP.3.0',
                'MSXML2.XMLHTTP',
                'Microsoft.XMLHTTP');
        // try every prog id until one works
        for (var i=0; i<XmlHttpVersions.length && !xmlHttp; i++)
        {
            try
            {
                // try to create XMLHttpRequest object
                xmlHttp = new ActiveXObject(XmlHttpVersions[i]);
            }
            catch (e) {}
        }
    }
    // return the created object or display an error message
    if (!xmlHttp)
        alert("Error creating the XMLHttpRequest object.");
    else
        return xmlHttp;
}
// read a file from the server

function process(idtag, url)
{
	var xmlHttp = createXmlHttpRequestObject();
	// only continue if xmlHttp isn't void
	if (xmlHttp)
    {
        // try to connect to the server
        try
        {
            if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0) {
                // initiate reading a file from the server
                // xmlHttp.open("GET", "books.xml", true);
				xmlHttp.open("GET", url, true);
				
				xmlHttp.onreadystatechange = function() {
					if (xmlHttp.readyState == 4)
					{
						if (xmlHttp.status == 200)
						{
							try
							{
								field = document.getElementById(idtag);
								field.innerHTML = xmlHttp.responseText;
							}
							catch(e)
							{
								alert("Error reading the response: " + e.toString());
							}
						}
						else
						{
							alert("There was a problem retrieving the data:\n" +
									xmlHttp.statusText);
						}
					}
				}
                xmlHttp.send(null);
            } else {
                setTimeout("process('" + idtag + "', '" + url + "')", 500);
            }
        }
        // display the error in case of failure
        catch (e)
        {
            alert("Can't connect to server:\n" + e.toString());
        }
    }
}