348 

   349 function ajaxScrollInit(urlFormat,

   350                         nextHash,

   351                         nextHashRegex,

   352                         containerSelector,

   353                         messageFormat) {

   354     updateInitiated = false;

   355     container = document.querySelector(containerSelector);

   356 

   357     function scrollHandler() {

   358         if (updateInitiated) {

   359             return;

   360         }

   361 

   362         var scrollHeight = document.documentElement.scrollHeight;

   363         var clientHeight = document.documentElement.clientHeight;

   364         var scrollTop = document.body.scrollTop

   365             || document.documentElement.scrollTop;

   366 

   367         if (scrollHeight - (scrollTop + clientHeight) < 50) {

   368             updateInitiated = true;

   369 

   370             if (!nextHash) {

   371                 return;

   372             }

   373 

   374             makeRequest(

   375                 format(urlFormat, {hash: nextHash}),

   376                 'GET',

   377                 function onstart() {

   378                 },

   379                 function onsuccess(htmlText) {

   380                     var m = htmlText.match(nextHashRegex);

   381                     nextHash = m ? m[1] : null;

   382 

   383                     var doc = docFromHTML(htmlText);

   384                     var nodes = doc.querySelector(containerSelector).children;

   385                     while (nodes.length) {

   386                         var node = nodes[0];

   387                         node = document.adoptNode(node);

   388                         container.appendChild(node);

   389                     }

   390                     process_dates();

   391                 },

   392                 function onerror(errorText) {

   393                 },

   394                 function oncomplete() {

   395                     updateInitiated = false;

   396                     scrollHandler();

   397                 }

   398             );

   399         }

   400     }

   401 

   402     window.addEventListener('scroll', scrollHandler);

   403     window.addEventListener('resize', scrollHandler);

   404     scrollHandler();

   405 }