How to include JSON data in javascript synchronously without parsing?

Question

I want to load a JSON file from my own server containing an array into a javascript Object variable.
I would like to do it at the beginning of page load in a synchronous way because data is needed during page load.

I managed to use jQuery.getJSON but this is asynch ajax and it seems a little overkill.

Is there a way to load JSON in a synch way without doing your own parsing?
(more or less like using a <script language="JavaScript" src="MyArray.json"></script>)

Thanks in advance for any help, hope it makes sense since I am a javascript newbie. Paolo

Answer 1

getJSON() is simply shorthand for the ajax() function with the dataType:'json' set. The ajax() function will let you customize a lot about the request.

$.ajax({   url: 'MyArray.json',   async: false,   dataType: 'json',   success: function (response) {     // do stuff with response.   } }); 

You still use a callback with async:false but it fires before it execution continues on from the ajax call.

Answer 2

Here you go:

// Load JSON text from server hosted file and return JSON parsed object function loadJSON(filePath) {   // Load json file;   var json = loadTextFileAjaxSync(filePath, "application/json");   // Parse json   return JSON.parse(json); }     // Load text with Ajax synchronously: takes path to file and optional MIME type function loadTextFileAjaxSync(filePath, mimeType) {   var xmlhttp=new XMLHttpRequest();   xmlhttp.open("GET",filePath,false);   if (mimeType != null) {     if (xmlhttp.overrideMimeType) {       xmlhttp.overrideMimeType(mimeType);     }   }   xmlhttp.send();   if (xmlhttp.status==200 && xmlhttp.readyState == 4 )   {     return xmlhttp.responseText;   }   else {     // TODO Throw exception     return null;   } } 

NOTE: This code works in modern browsers only - IE8, FF, Chrome, Opera, Safari. For obosolete IE versions you must use ActiveX, let me know if you want that I will tell you how ;)