存在具有警报功能的回调被触发，并且没有警报就不会触发吗？

Question

When the alert function is present (shown below), the callback function gets fired and everything works. When the alert function is not present, the callback function never gets fired.

  function getTableData(tableName, startRow, endRow, callback)
  {
    CK.getData = $.getJSON("getTableData.php",{tN: tableName, sR: startRow, eR: endRow}, function(dataTable){});

    alert("test"); 
    CK.getData.done(function()
    {
       // load data inside table using an $.each function...
       callback(); // works only when the alert function above is present..
    });
  }

   getTableData(tableName, startRow, endRow, function()
   {
      $(".logTable").after($addRowData); 
   });

Answer 1

The problem was the ajax function is non-blocking (asynchronous), meaning the each loop continues on without waiting for a response. By the time you get a response from any of the getJSON call you've finished iteration.

I wrap the ajax function within a closure:

  (function(tableName, startRow, endRow)
  { 
      getTableData(tableName, startRow, endRow, function()
      {
        $(".logTable").after($addRowData); 
      });

  })(tableName, startRow, endRow);

And set the async variable within $.ajax object to false for sync. communication.