Develop Reference

How can I force JavaScript to wait until after a dynamically added script file has completed loading?

I'm trying to write a function which will append a javascript file to the DOM, but I am looking to have the rest of the code wait until the newly added JS file is completely loaded. Here is an example of what I am trying to accomplish, although this code doesn't work properly:
$(document).ready(function () {
var newScript = document.createElement("script");
newScript.setAttribute("type", "text/javascript");
newScript.src = "http://www.domain.com/script.js";
document.getElementsByTagName("body")[0].appendChild(newScript);
$(newScript).ready(function () { // This is the idea of what I'm trying to do, but this doesn't seem to actually wait until the new file is completely loaded.
foo.bar(); // foo is a new global variable which is declared in the newScript. This causes an error "foo is not defined".
// Here is where more code I wish to execute should continue.
});
});

As Musa mentioned in the comments above. Use jQuery's getScript and use the success callback function to trigger your other functions.

If you want more robust module loading functionality, then require.js works great in this capacity. Check out: http://requirejs.org/docs/why.html for an overview. I use require.js specifically for lazy-loading script modules.

Using jQuery (as you've tagged), it's extremely easy:
$.getScript('/script.js', function() {
foo.bar();
});

There's a few different ways to do this... via libraries or "by hand," so to speak, using only the browser APIs and straight JavaScript. For an answer on how to do this in JS only, look here for Stoyan's post to give you guidance. Basically, the gist of it is setting an event handler to both the script's unload and onreadystatechange properties and then check to see if the readyState is "loaded" or "complete" (if it exists at all). It would look something like this:
var done = false;
newScript.onload = newScript.onreadystatechange = function () {
if (!done && (!newScript.readyState || newScript.readyState === "loaded" || newScript.readyState === "complete)) {
done = true;
// run your actual code here
}
};

Handling code which relies on jQuery before jQuery is loaded

I'd like to follow the general guideline of putting all JavaScript at the very bottom of the page, to speed up loading time and also to take care of some pesky issues with conflicting jQuery versions in a web app (Django).
However, every so often I have some code, code which depends on jQuery, but which must be further up on the page (basically the code can't be moved to the bottom).
I'm wondering if there's an easy way to code this so that even though jQuery is not yet defined the code works when jQuery is defined.
The following seems, I have to say, like overkill but I don't know of another way to do it:
function run_my_code($) {
// jquery-dependent code here
$("#foo").data('bar', true);
}
var t = null;
function jquery_ready() {
if (window.jQuery && window.jQuery.ui) {
run_my_code(window.jQuery);
} else {
t = window.setTimeout(jquery_ready, 100);
}
}
t = window.setTimeout(jquery_ready, 100);
Actually, I might need to use code more than once in a page, code that doesn't know about other code, so even this probably won't work unless I rename each jquery_ready to something like jquery_ready_guid, jquery_ready_otherguid and so on.
Clarification
Just so this is clear, I am putting the include to JavaScript (<script type="text/javascript" src="jquery.min.js" />) at the very bottom of the page, just before the </body>. So I can't use the $.

Simple use pure javascript version of $(document).ready();:
document.addEventListener("DOMContentLoaded", function(event) {
//you can use jQuery there
});

Your way is the only way that I know of, though I would ensure that the scoping is a little tighter:
(function() {
var runMyCode = function($) {
// jquery-dependent code here
$("#foo").data('bar', true);
};
var timer = function() {
if (window.jQuery && window.jQuery.ui) {
runMyCode(window.jQuery);
} else {
window.setTimeout(timer, 100);
}
};
timer();
})();
Update
Here's a little deferred loader I cobbled together:
var Namespace = Namespace || { };
Namespace.Deferred = function () {
var functions = [];
var timer = function() {
if (window.jQuery && window.jQuery.ui) {
while (functions.length) {
functions.shift()(window.jQuery);
}
} else {
window.setTimeout(timer, 250);
}
};
timer();
return {
execute: function(onJQueryReady) {
if (window.jQuery && window.jQuery.ui) {
onJQueryReady(window.jQuery);
} else {
functions.push(onJQueryReady);
}
}
};
}();
Which would then be useable like so:
Namespace.Deferred.execute(runMyCode);

The best way I have found is to write the code in a function and call the function after jquery is loaded:
function RunAfterjQ(){
// Codes that uses jQuery
}
<script type="text/javascript" src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
<script type="text/javascript">
RunAfterjQ();
</script>
Update: For master pages, you can define an array to push functions in the head of the master page:
var afterJQ = [];
then at the bottom of master page run all the functions pushed in to this array:
<script type="text/javascript" src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
<script type="text/javascript">
for(var i = 0; i < afterJQ.length; i++) afterJQ[i]();
</script>
Everywhere that you need to use javascript that relies on jQuery and is before jQuery is defined just push it in to this array:
afterJQ.push( function() {
// this code will execute after jQuery is loaded.
});

Here is a way to write injected code that will be run only after jQuery loads (whether synchronously or asynchronously).
<script>
if ( ! window.deferAfterjQueryLoaded ) {
window.deferAfterjQueryLoaded = [];
Object.defineProperty(window, "$", {
set: function(value) {
window.setTimeout(function() {
$.each(window.deferAfterjQueryLoaded, function(index, fn) {
fn();
});
}, 0);
Object.defineProperty(window, "$", { value: value });
},
configurable: true
});
}
window.deferAfterjQueryLoaded.push(function() {
//... some code that needs to be run
});
</script>
What this does is:
Defines deferAfterjQueryLoaded lazily, so you don't need to inject that into head.
Defines a setter for window.$. When jQuery loads, one of the last things it does is assign to the global $ variable. This allows you to trigger a function when that happens.
Schedules the deferred functions to run as soon as possible after the jQuery script finishes (setTimeout(..., 0);).
Has the setter remove itself.
For complete cleanliness you could have the scheduled function remove deferAfterjQueryLoaded as well.

How about:
<script>
window.deferAfterjQueryLoaded = [];
window.deferAfterjQueryLoaded.push(function() {
//... some code that needs to be run
});
// ... further down in the page
window.deferAfterjQueryLoaded.push(function() {
//... some other code to run
});
</script>
<script src="jquery.js" />
<script>
$.each(window.deferAfterjQueryLoaded, function(index, fn) {
fn();
});
</script>
This works because every script here is completely blocking. Meaning the creation of the deferAfterjQueryLoaded array and all functions being created and pushed to that array occur first. Then jQuery completely loads. Then you iterate through that array and execute each function. This works if the scripts are in separate files as well just the same way.
If you ALSO want DOMReady to fire you can nest a $(function() {}) inside of one of your deferAfterjQueryLoaded functions like such:
window.deferAfterjQueryLoaded.push(function() {
$(function() {
console.log('jquery loaded and the DOM is ready');
});
console.log('jquery loaded');
});
Ultimately, you should really refactor your code so everything is actually down at the bottom, and have a system conducive to that model. It is much easier to understand everything occurring and more performant (especially if you have separate scripts).

I have this same problem, but with a ton of files, I use headjs to manage the loading, it's only 2kb so there isn't really a problem, for me anyway, of putting in the header. Your code then becomes,
head.ready(function(){
$...
});
and at the bottom of the page,
head.js('/jquery.min.js');

You should be able to do this on a document ready event.

function jQueryGodot(code)
{
if (window.jQuery)
{
code(window.jQuery);
}
else
{
if (!window.$)
{
window.$ = { codes: [] };
window.watch('$', function(p, defered, jQuery) {
jQuery.each(defered.codes, function(i, code) {
code(jQuery);
});
return jQuery;
});
}
window.$.codes.push(code);
}
}
jQueryGodot(function($) {
$('div').html('Will always work!');
})
Working example on JSFiddle.
Code passed to jQueryGodot function will always be executed no matter if it is called before or after jQuery is loaded.
The solution relies on Object.watch which requires this polyfill (660 bytes minified) in most of the browsers: https://gist.github.com/adriengibrat/b0ee333dc1b058a22b66

You can defer all calls like jQuery(function(){...}) without the loop of a setTimeout: https://jsfiddle.net/rL1f451q/3/
It is collecting every jQuery(...) call into an array until jQuery is not defined, then the second code executes them when jQuery is available.
Put this in the head or the beginning of the body:
<!-- jQuery defer code body: deferring jQuery calls until jQuery is loaded -->
<script>
window.jQueryQ = window.jQueryQ || [];
window.$ = window.jQuery = function(){
window.jQueryQ.push(arguments);
}
</script>
<!-- end: jQuery defer code body -->
And this at the very end of the body, after the jQuery script:
<!-- jQuery deferring code footer: add this to the end of body and after the jQuery code -->
<script>
jQuery(function(){
jQuery.each(window.jQueryQ||[],function(i,a){
// to understand why setTimeout 0 is useful, see: https://www.youtube.com/watch?v=8aGhZQkoFbQ, tldr: having a lot of calls wont freeze the website
setTimeout(function(){
jQuery.apply(this,a);
},0);
});
});
</script>
<!-- end: jQuery deferring code footer -->

I've wrote simple js code for handle such cases: https://github.com/Yorkii/wait-for
Then you can use it like this
waitFor('jQuery', function () {
//jQuery is loaded
jQuery('body').addClass('done');
});
You can even wait for multiple libraries
waitFor(['jQuery', 'MyAppClass'], function () {
//Both libs are loaded
});

I'm posting my answer using a JavaScript promise. It works, it is simple and reusable.
The advantage is, that the code get's executed as soon as jQuery is loaded, no matter how early or late on the page.
But, I'm by far not as experienced like some other people in this thread. So I'd love my answer to be peer reviewed. I'd like to know if it really is a valid solution and what the downsides are.
Write an objectExists function with a promise as high up in the code as you want.
function jqueryExists() {
return new Promise(function (resolve, reject) {
(function waitForJquery() {
if (jQuery) return resolve();
setTimeout(waitForJquery, 30);
})();
});
}
Then add your function which depends on jQuery. As far as I understand, it won't block any other script from execution, and the page will load just fine even if jQuery is loaded much later.
jqueryExists().then(function(){
// Write your function here
}).catch(function(){
console.log('jQuery couldn\'t be loaded');
})
jQuery can now be loaded after this code, and the function will execute as soon as jQuery is available.

How to unload a javascript from an html?

How can I unload a JavaScript resource with all its defined objects from the DOM?
Im developing a simple framework that enables to load html fragments into a "main" html. Each fragment is self contained and may include references to additional JS and CSS files. The JS and CSS resources are parsed and dynamically added to the html. When the fragment is removed/replaced from the DOM I want to remove its JS and CSS.
If I remove the script element in the example below, the functions defined in page1.js are still available.
<html>
<head>
<script src="page1.js" type="text/javascript"></script>
</head>
<body>
...
Is there a way to unload page1.js objects from the DOM?
========= The test code I use =======
I tried the advice i got in the comments below; to delete the added objects using a cleanup function - but even this fails. The sources i used for testing:
<html>
<head>
<script type="text/javascript">
function loadJSFile(){
var scriptTag = document.createElement("script");
scriptTag.setAttribute("type", "text/javascript");
scriptTag.setAttribute("src", "simple.js");
var head = document.getElementsByTagName("head")[0];
head.appendChild(scriptTag);
}
function unloadJSFile(){
delete window.foo;
delete window.cleanup;
alert("cleanedup. typeof window.foo is " + (typeof window.foo));
}
</script>
</head>
<body>
Hello JavaScript Delete
<br/>
<button onclick="loadJSFile();">Click to load JS</button>
<br/>
<button onclick="foo();">call foo()</button>
<br/>
<button onclick="unloadJSFile();">Click to unload JS</button>
</body>
</html>
simple.js source:
var foo = function(){
alert("hello from foo");
}

This cannot be done.
When a script is executed, function definitions are added to the global window object. There may be debugging symbols attached to the function that indicate where the function came from, but this information is not available to scripts.
About the only way you could achieve something like this would be to create a pseudo-namespace in the script and then throw away that whole namespace when you are done with it. However, this question hints to me that you are trying to do something the wrong way. Perhaps elaborating on your scenario would help us provide alternate solutions.

No, that is not possible. You could build a simple cleanup function that removes all variables that were defined in that file:
var foo = 'bar';
var cleanup = function () {
delete window.foo;
delete window.cleanup;
};
// unload all resources
cleanup();
Another approach would be to use a modular object structure for your fragments, that clean up after themselves. That involves a slightly higher overhead but is probably worth it, as it makes the code much easier to read and maintain:
// creates the object using the second parameter as prototype.
// .create() is used as constructor
GlobalModuleHandlerThingy.addModule('my_module', {
create: function () {
this.foo = 'bar';
return this;
},
foo: null,
destroy: function () {
// unload events, etc.
}
});
GlobalModuleHandlerThingy.getModule('my_module').foo; // => bar
GlobalModuleHandlerThingy.unloadModule('my_module'); // calls .destroy() on the module and removes it.

perhaps you need to consider conditionally loading it rather than conditionally unloading it...

you can make them = null
function fnc1 (){
}
window.fnc1 = null
//or
window["fnc1"] = null

If you need to unload a specific object, it's fairly easy: just set it to {}
ie: myobj = {};
So if you know what objects are created in a particular include, it won't be hard at all.
On the other hand, if you don't know what objects are created in a particular include, there isn't a mechansim to find out - you can't ask Javascript to tell you what was defined in a particular include.
However, I would say that if you don't know what objects are being loaded in a particular javascript file, you're probably not doing yourself any favours in loading it (you should always have a reasonable idea what code does in your site), or in trying to unload it manually (if you don't know what it does, that implies its a third party include, which means that unsetting it manually is likely to break things).

Was researching for something like that myself and thought I'll post my findings
Wrap your stuff in a global namespace in js file so it can be removed easily, ie
var stuff = { blabla: 1, method: function(){} };
When you need to get rid of it, simply set stuff = {}, or null even
Remove script tag from page
*** If you use requirejs - require js remove definition to force reload
Note: as long as you don't reference modules inside the namespace from anywhere else everything will be collected by GC and you are good to go.

I figured a trick for this. I was wondering here days finding an answer for this and I just realized a perfect trick to do this without trying to unload the java Script. only you have to do is create a global variable like currentPage in your main page's java script and when you loading the page assign the page name to currentPage . then in every other .js file use $('document').ajaxComplete() insted of $('document').ready() add an if statement as first line inside every $('document').ajaxComplete() function. set it to check currentPage variable equals to a new page name. add all other events inside if statement. i don't know English very well so check my code. and This is my first answer here so sorry if i make some mistakes.
main.html
<body>
<div id='container></div>
<button id="load1">
<button id="load1">
</body>
main.js
var currentPage = "";
$(document).ready(function () {
$('#load1').click(function () {
loadSource('page1', 'body');
});
$('#load2').click(function () {
loadSource('page2', 'body');
});
});
function loadSource( page, element){
currentPage = page;
$('#container').load('views/' + page + '.php', element);
$.getScript('js/' + page + '.js');
$('#css').prop('disabled', true).remove();
$('head').append('<link rel="stylesheet" href="css/' + page + '.css" type="text/css" />');
}
all of my pages scripts and styles are in seperate folders views, js, css.
page1.html
<body>
<button id="test1">
<button id="test2">
</body>
page1.js
$(document).ajaxComplete(function () {
if(currentPage == 'page1'){
/*$('#test1').click(function () {
console.log('page1');
});*/
$('#test2').click(function () {
console.log('page1');
});
}
});
page2.html
<body>
<button id="test1">
<button id="test2">
</body>
page2.js
$(document).ajaxComplete(function () {
if(currentPage == 'page2'){
$('#test1').click(function () {
console.log('page2');
});
/*$('#test2').click(function () {
console.log('page2');
});*/
}
});
i commented one button in each script to check if that button still has old script's affect.

Trigger $document.ready (so AJAX code I can't modify is executed)

My requirements are the following:
I've got a rich webpage that at a certain moment loads a bunch of HTML in a div, via AJAX.
The HTML I retrieve does have javascript (<script>...</script>)
The retrieved javascript contains $('document').ready( ... ) parts
I can not modify the retrieved javascript; it comes from an external lib
I've got a javascript function that is called when the AJAX is loaded. I'm trying to "trick it" into executing by doing:
function AjaxLoaded() {
$('document').trigger('ready');
}
That doesn't cut it, I'm afraid.
I've seen several responses on Stack Overflow that "evade" this question by changing the code that is returned on the AJAX (make it a function and call it after loading, or just remove the $(document).ready()). I need to stress out that I can't change the retrieved code on this case.

Afer some research i created a way to get it to work.
here is my test that shows it working: http://www.antiyes.com/test/test2.php
here is the relevant code:
<script>
// easy copy of an array
Array.prototype.copy = function() {
return [].concat(this);
};
// this function is added to jQuery, it allows access to the readylist
// it works for jQuery 1.3.2, it might break on future versions
$.getReadyList = function() {
if(this.readyList != null)
this.myreadylist = this.readyList.copy();
return this.myreadylist;
};
$(document).ready(function() {
alert("blah");
});
</script>
<script>
// this should be added last so it gets all the ready event
$(document).ready(function() {
readylist = $.getReadyList();
});
</script>
then in the body I have:
<input type="button" onclick="$(readylist).each(function(){this();});" value="trigger ready" />
basically what i did was add a function to jQuery that copies the readyList before it's cleared out, then it will be available to be used by you.
it looks like the code below doesnt work:
function AjaxLoaded() {
$(document).trigger('ready');
}
drop the quotes around document.

Since the jQuery readyList is not exposed as of version 1.4 (discussed here) the nice solutions above are broken.
A way around this is by creating your own readyList, through overriding the original jQuery-ready method. This needs to be done before other scripts that use the original ready method are loaded. Otherwise just the same code as John/Kikito:
// Overrides jQuery-ready and makes it triggerable with $.triggerReady
// This script needs to be included before other scripts using the jQuery-ready.
// Tested with jQuery 1.7
(function(){
var readyList = [];
// Store a reference to the original ready method.
var originalReadyMethod = jQuery.fn.ready;
// Override jQuery.fn.ready
jQuery.fn.ready = function(){
if(arguments.length && arguments.length > 0 && typeof arguments[0] === 'function') {
readyList.push(arguments[0]);
}
// Execute the original method.
originalReadyMethod.apply( this, arguments );
};
// Used to trigger all ready events
$.triggerReady = function() {
$(readyList).each(function(){this();});
};
})();
I'm not sure whether it is advisable to override the ready method. Feel free to advise me on that. I have not yet found any side effects myself though.

Just in case anyone needs it, I refined John's solution a bit so it could be used directly as an included javascript file.
// jquery_trigger_ready.js
// this function is added to jQuery, it allows access to the readylist
// it works for jQuery 1.3.2, it might break on future versions
$.getReadyList = function() {
if(this.readyList != null) { this.myreadylist = [].concat(this.readyList); }
return this.myreadylist;
};
$(document).ready(function() {
readylist = $.getReadyList();
});
$.triggerReady = function() {
$(readylist).each(function(){this();});
}
Including this file after including jquery allows for triggering ready by invoking $.triggerReady(). Example:
<html>
<head>
<title>trigger ready event</title>
<script src="test2_files/jquery-1.js" type="text/javascript"></script>
<script src="jquery_trigger_ready.js" type="text/javascript"></script>
</head>
<body>
<input onclick="$.triggerReady();" value="trigger ready" type="button">
<script type="text/javascript">
$(document).ready(function(){
alert("blah");
});
</script>
</body>
</html>
By the way, I wanted to make it $(document).triggerReady(). If anyone is willing to share some advice on that, ill be appreciated.

We had the same problem and solved it another way.
Instead of
$(document).ready(function () {
$('.specialClass').click(....
We used :
$(document).bind('ready', function(event) {
$('.specialClass', event.target).click(..
jQuery will trigger a "ready" event on the document as usual. When we load the content of a new div via ajax, we can write:
loadedDiv.trigger('ready')
And have all the initialization performed only on the div, obtaining what expected.

Simone Gianni's Answer I think is the most elegant and clean.
and you can even simplify it to become even more easy to use:
jQuery.fn.loadExtended = function(url,completeCallback){
return this.load(url,function(responseText, textStatus, XMLHttpRequest) {
if (completeCallback !== undefined && completeCallback !== null) {
completeCallback(responseText, textStatus, XMLHttpRequest);
}
$(this).trigger("ready");
});
};
So, now instead of using:
$(".container").load(url,function(responseText, textStatus, XMLHttpRequest) {
$(this).trigger("ready");
});
you can just use:
$(".container").loadExtended("tag_cloud.html");
or:
$(".container").loadExtended("tag_cloud.html",function(){
alert('callback function')
});
This has the advantage of only applying the trigger on the div that's being updated.

If your new loaded HTML contain <script> elements and you try insert it into main HTML with pure JS (element.innerHTML = newHTML), then $(document).ready handlers at newHTML and wrapped functions like (function() { /* some functions */ })(); - will not execute because JQuery unbind 'ready' event after first triggering and you can not trigger it repeatly. PS. But you can use $.holdReady(true) and trigger when need.
So, try insert code with jquery method, $(element).html(newHTML). This solved similar problem for me, seems jquery handle js before inserting. Using this method you also will not see the <script> elements among DOM nodes (at browser's Elements Inspector for ex.)

How to detect if javascript files are loaded?

Is there an event that fires when JavaScript files are loaded? The problem came up because YSlow recommends to move JavaScript files to the bottom of the page. This means that
$(document).ready(function1) is fired before the js file that contains the code for function1 is loaded.
How to avoid this kind of situation?

I don't have a reference for it handy, but script tags are processed in order, and so if you put your $(document).ready(function1) in a script tag after the script tags that define function1, etc., you should be good to go.
<script type='text/javascript' src='...'></script>
<script type='text/javascript' src='...'></script>
<script type='text/javascript'>
$(document).ready(function1);
</script>
Of course, another approach would be to ensure that you're using only one script tag, in total, by combining files as part of your build process. (Unless you're loading the other ones from a CDN somewhere.) That will also help improve the perceived speed of your page.
EDIT: Just realized that I didn't actually answer your question: I don't think there's a cross-browser event that's fired, no. There is if you work hard enough, see below. You can test for symbols and use setTimeout to reschedule:
<script type='text/javascript'>
function fireWhenReady() {
if (typeof function1 != 'undefined') {
function1();
}
else {
setTimeout(fireWhenReady, 100);
}
}
$(document).ready(fireWhenReady);
</script>
...but you shouldn't have to do that if you get your script tag order correct.
Update: You can get load notifications for script elements you add to the page dynamically if you like. To get broad browser support, you have to do two different things, but as a combined technique this works:
function loadScript(path, callback) {
var done = false;
var scr = document.createElement('script');
scr.onload = handleLoad;
scr.onreadystatechange = handleReadyStateChange;
scr.onerror = handleError;
scr.src = path;
document.body.appendChild(scr);
function handleLoad() {
if (!done) {
done = true;
callback(path, "ok");
}
}
function handleReadyStateChange() {
var state;
if (!done) {
state = scr.readyState;
if (state === "complete") {
handleLoad();
}
}
}
function handleError() {
if (!done) {
done = true;
callback(path, "error");
}
}
}
In my experience, error notification (onerror) is not 100% cross-browser reliable. Also note that some browsers will do both mechanisms, hence the done variable to avoid duplicate notifications.

When they say "The bottom of the page" they don't literally mean the bottom: they mean just before the closing </body> tag. Place your scripts there and they will be loaded before the DOMReady event; place them afterwards and the DOM will be ready before they are loaded (because it's complete when the closing </html> tag is parsed), which as you have found will not work.
If you're wondering how I know that this is what they mean: I have worked at Yahoo! and we put our scripts just before the </body> tag :-)
EDIT: also, see T.J. Crowder's reply and make sure you have things in the correct order.

Take a look at jQuery's .load() http://api.jquery.com/load-event/
$('script').load(function () { });

Further to #T.J. Crowder 's answer, I've added a recursive outer loop that allows one to iterate through all the scripts in an array and then execute a function once all the scripts are loaded:
loadList([array of scripts], 0, function(){// do your post-scriptload stuff})
function loadList(list, i, callback)
{
{
loadScript(list[i], function()
{
if(i < list.length-1)
{
loadList(list, i+1, callback);
}
else
{
callback();
}
})
}
}
Of course you can make a wrapper to get rid of the '0' if you like:
function prettyLoadList(list, callback)
{
loadList(list, 0, callback);
}
Nice work #T.J. Crowder - I was cringing at the 'just add a couple seconds delay before running the callback' I saw in other threads.

I always make a call from the end of the JavaScript files for registering its loading and it used to work perfect for me for all the browsers.
Ex: I have an index.htm, Js1.js and Js2.js. I add the function IAmReady(Id) in index.htm header and call it with parameters 1 and 2 from the end of the files, Js1 and Js2 respectively. The IAmReady function will have a logic to run the boot code once it gets two calls (storing the the number of calls in a static/global variable) from the two js files.

Change the loading order of your scripts so that function1 was defined before using it in ready callback.
Plus I always found it better to define ready callback as an anonymous method then named one.

Like T.J. wrote: the order is defined (at least it's sequential when your browser is about to execute any JavaScript, even if it may download the scripts in parallel somehow). However, as apparently you're having trouble, maybe you're using third-party JavaScript libraries that yield some 404 Not Found or timeout? If so, then read Best way to use Google’s hosted jQuery, but fall back to my hosted library on Google fail.