Problem is to wait for all ajax calls to finish loading DOM. We count # of DOM elements and wait X secs if DOM changes page still loading. Adjust sec param for different websites

fireWhenReady.js

function callWhenReady(callBack, sec) {
  var wait4Loop = ( sec || 5 ) * 4; 
  var loopNum = 0;
  var domCount = document.querySelectorAll('*').length; //count DOM elements
  var i = setInterval(function(){ // after 1/4 of a sec
      var newCount = document.querySelectorAll('*').length; //count DOM elements
      if (domCount != newCount){ // new DOM elements are counted, page still loading
          domCount = newCount;
          loopNum = 0;
      }else{ // wait X sec if node count does not change, page likely finished loading.
          loopNum++;
          if (loopNum === wait4Loop){
              clearInterval(i);
              callBack();
          }
      }
  }, 250);
}
callWhenReady(function(){ alert("DOM is ready !!!")})