prevent multiple calls for map markers

example.js

var lockCounter;

function ajaxCallFunc()
{
  lockCounter++;
  var check = lockCounter;
  setTimeout(function(){
    if (check == lockCounter)
    {
      // This request was the last one to increment the counter

      // Bump up the counter so we can't fire another request
      //   while we fill this one
      lockCounter++;

      // PERFORMS AJAX STUFF HERE

    }
  },1000);
}

ajaxCallFunc(); // ignored
ajaxCallFunc(); // ignored
ajaxCallFunc(); // runs
// Wait a second or more
ajaxCallFunc(); // ignored
ajaxCallFunc(); // runs