// start ajaxrequest.js

// Following is a javascript function that makes a httprequest - AJAX. This is the AJAX bit and all that is needed in that manner.
// Only in this one we won't be using XML in our response, we will accept and handle
// pure text and html and display this response directly to the user within the
// desired <div id> tags. It can even be used to include pure html files as a substitute
// solution to the "old" frames method where as no php or other scripting language is nessesary on the server.
// but use it with care - it is not a search engine supported method and indexing will fail. Workaround for this is not included here

function MyAjaxRequest(target_div,file,check_div)
{
   var MyHttpRequest = false;
   var MyHttpLoading = '<p>Loading...</p>'; // or use an animated gif instead:
   //var MyHttpLoading = '<img src="loading.gif" border="0" alt="running" />';
   var ErrorMSG = 'Sorry - No XMLHTTP support in your browser';

   if(check_div)
   {
      var check_value = document.getElementById(check_div).value;
   }
   else
   {
      var check_value = '';
   }

   if(window.XMLHttpRequest) // client use Firefox, Opera etc - Non Microsoft product
   {
      try
      {
         MyHttpRequest = new XMLHttpRequest();
      }
      catch(e)
      {
         MyHttpRequest = false;
      }
   }
   else if(window.ActiveXObject) // client use Internet Explorer
   {
      try
      {
         MyHttpRequest = new ActiveXObject("Msxml2.XMLHTTP");
      }
      catch(e)
      {
         try
         {
            MyHttpRequest = new ActiveXObject("Microsoft.XMLHTTP");
         }
         catch(e)
         {
            MyHttpRequest = false;
         }
      }
   }
   else
   {
      MyHttpRequest = false;
   }

   if(MyHttpRequest) // browser supports httprequest
   {
      var random = Math.random() * Date.parse(new Date()); // make a random string to prevent caching

      var file_array = file.split('.'); // prepare to check if we have a query string or a html/htm file
      if(file_array[1] == 'php') // no query string, just calling a php file
      {
         var query_string = '?rand=' + random;
      }
      else if(file_array[1] == 'htm' || file_array[1] == 'html') // calling a htm or html file
      {
         var query_string = '';
      }
      else // we have presumable a php file with a query string attached
      {
         var query_string = check_value + '&rand=' + random;
      }

      MyHttpRequest.open("get", url_encode(file + query_string), true); // <-- run the httprequest using GET

      // handle the httprequest
      MyHttpRequest.onreadystatechange = function ()
      {
         if(MyHttpRequest.readyState == 4) // done and responded
         {
            document.getElementById(target_div).innerHTML = MyHttpRequest.responseText; // display result
         }
         else
         {
            document.getElementById(target_div).innerHTML = MyHttpLoading; // still working
         }
      }
      MyHttpRequest.send(null);
   }
   else
   {
      document.getElementById(target_div).innerHTML = ErrorMSG; // the browser was unable to create a httprequest
   }
}
// end of "AJAX" function


// Here follows a function to urlencode the string we run through our httprequest, it has nothing to do with AJAX itself
// If you look carefully in the above httprequest you se that we use this url_encode function around the file and query_string
// This is very handy since we are using GET in our httprequest and for instance
// any occurrance of the char # (from textboxes etc) will brake the string we are sending to our file - we don't want that to brake!
// It will also convert spaces to +

function url_encode(string)
{
   var string;
   var safechars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz/-_.&?=";
   var hex = "0123456789ABCDEF";
   var encoded_string = "";
   for(var i = 0; i < string.length; i++)
   {
      var character = string.charAt(i);
      if(character == " ")
      {
         encoded_string += "+";
      }
      else if(safechars.indexOf(character) != -1)
      {
         encoded_string += character;
      }
      else
      {
         var hexchar = character.charCodeAt(0);
         if(hexchar > 255)
         {
            encoded_string += "+";
         }
         else
         {
            encoded_string += "%";
            encoded_string += hex.charAt((hexchar >> 4) & 0xF);
            encoded_string += hex.charAt(hexchar & 0xF);
         }
      }
   }
   return encoded_string;
}
// end of urlencode function


// end .js file