/** Our function that initializes when the page
    is finished loading. */
function initialize() {
   // initialize the DHTML History framework
   dhtmlHistory.initialize();
   
   // add ourselves as a DHTML History listener
   dhtmlHistory.addListener(handleHistoryChange);
}

/** Handles history change events. */
function handleHistoryChange(newLocation, 
                             historyData) {
   // if there is no location then display
   // the default, which is the index_main
   if (newLocation == "") {
      newLocation = "section:main_index";
   }
   
   // extract the section to display from
   // the location change; newLocation will
   // begin with the word "section:" 
   newLocation = 
         newLocation.replace(/section\:/, "");
   
   // update the browser to respond to this
   // DHTML history change
   displayLocation(newLocation, historyData);
}

/** Displays the given location in the 
    right-hand side content area. */
function displayLocation(newLocation,
                         sectionData) {
	changeMain(newLocation + ".php");
}