/****************************************************************************
* AJAX Wrapper
*
* Author: Timothy M. Crider (timcrider@gmail.com)
*
* Description:
* Multiple AJAX handler, written to handle the problem of the old single
* 'req' format. Each indivual request is identified by using a unique
* namespace. Global variable 'TA' is created at the end of this file.
*
*****************************************************************************
*
* TODO
*
* Add Error Stack
*
*****************************************************************************
*
* EXAMPLE
*
*
*
*
*
*
*
*
*
*
*
This is main content
*
*
*
****************************************************************************/
//////////////////////////////////////////////////////////////////////////////
//
// AJAX STRUCT
//
//////////////////////////////////////////////////////////////////////////////
function t_ajax_request(ns, url, _function)
{
this.req = null; // Request Pointer
this.ns = ns; // Namespace Identifier
this.url = url; // Web Address
this.method = "GET"; // Posting Method (to be added)
this.result = false; // Resulting HTML/XML/Text
this._function = _function; // Request Processing Function
} // End 't_ajax_request'
//////////////////////////////////////////////////////////////////////////////
//
// INIT AJAX CONTAINER
//
//////////////////////////////////////////////////////////////////////////////
function t_ajax()
{
// Variables
this.req = Array(); // Request Stack
this.size = 0; // Request Stack Size
this.requests = 0; // Total Requests Processed
// Methods
this.getLength = t_ajax_getLength; // Get Request Stack Length
this.findRequest = t_ajax_findRequest; // Find Request In Stack
this.addRequest = t_ajax_addRequest; // Add Requeest To Stack
this.send = t_ajax_processRequest; // Send Request
this.fetchText = t_ajax_responseText; // Fetch Request Text
this.fetchXML = t_ajax_responseXML; // Fetch Request XML
} // End 'init_t_ajax'
//////////////////////////////////////////////////////////////////////////////
//
// Get size of the request stack
//
//////////////////////////////////////////////////////////////////////////////
function t_ajax_getLength()
{
// Return the size of the request stack
return this.req.length;
} // End 't_ajax_getLength'
//////////////////////////////////////////////////////////////////////////////
//
// Find the request in the stack
//
//////////////////////////////////////////////////////////////////////////////
function t_ajax_findRequest(ns)
{
// Cycle through request stack
for (var i = 0; i < this.getLength(); i++)
{
// Compare request namespace to current stack
if (ns == this.req[i].ns)
return this.req[i];
}
// Namespace not in stack
return false;
} // End 't_ajax_findRequest'
//////////////////////////////////////////////////////////////////////////////
//
// Add a request to the stack
//
//////////////////////////////////////////////////////////////////////////////
function t_ajax_addRequest(ns, url, _function)
{
// Find Current Request
var _c = this.findRequest(ns);
// If request exists, update the request info
if (_c)
{
_c.url = url;
_c._function = _function;
return;
}
// Create the new request and push it on the stack
var _t = this.getLength();
this.req[_t] = new t_ajax_request(ns, url, _function);
return;
} // End 't_ajax_addRequest'
//////////////////////////////////////////////////////////////////////////////
//
// Process the request and handle result storage
//
//////////////////////////////////////////////////////////////////////////////
function t_ajax_processRequest(ns)
{
// Find the current request
var t_ns = this.findRequest(ns);
// Test Stack
if (!t_ns)
{
return false;
}
// Test for AJAX compat
if(window.XMLHttpRequest)
{
// Try to create the request
try
{
t_ns.req = new XMLHttpRequest();
}
catch(e)
{
t_ns.req = false;
}
}
else if(window.ActiveXObject)
{
try
{
t_ns.req = new ActiveXObject('Msxml2.XMLHTTP');
}
catch(e)
{
try
{
t_ns.req = new ActiveXObject('Microsoft.XMLHTTP');
}
catch(e)
{
t_ns.req = false;
}
}
}
// Check request creation
if (t_ns.req)
{
// Assign processing function
t_ns.req.onreadystatechange = t_ns._function;
// Setup the request
t_ns.req.open(t_ns.method, t_ns.url, true);
// Send the request
t_ns.req.send('');
// Count the request
this.requests++;
}
return;
} // End 't_ajax_processRequest'
//////////////////////////////////////////////////////////////////////////////
//
// Process Text Output
//
//////////////////////////////////////////////////////////////////////////////
function t_ajax_responseText(ns)
{
// Fetch the request
var r = TA.findRequest(ns);
// Check to make sure request exists
if (!r.req)
return null;
// Check for response
if (r.req.responseText)
{
// Store response
var out = r.req.responseText;
// Reset the request. (Fix for double assignment)
r.req = false;
return out;
}
return;
} // End 't_ajax_responseText'
//////////////////////////////////////////////////////////////////////////////
//
// Process XML Output
//
//////////////////////////////////////////////////////////////////////////////
function t_ajax_responseXML(ns)
{
// Fetch the request
var r = TA.findRequest(ns);
// Check to make sure request exists
if (!r.req)
return null;
// Check for response
if (r.req.responseXML)
{
// Store response
var out = r.req.responseXML;
// Reset the request. (Fix for double assignment)
r.req = false;
return out;
}
return;
} // End 't_ajax_responseXML'
function emptySend(url)
{
TA.addRequest('__throwaway__', url, _emptyFunction);
TA.send('__throwaway__');
}
//////////////////////////////////////////////////////////////////////////////
//
// Create The TA object (global)
//
//////////////////////////////////////////////////////////////////////////////
var TA = new t_ajax();