We Keep Coding

How to preload all my javascript files before loading my website body?

This question have been already treated on the internet but i dont find a simple answer.
I would like to load only thoses javascript files and css, before starting to run the body my website.
I'm using packery.js, but when my website appears at first, my divs are misplaced. When i reload the page, everything gets back in place.
Is there a way to say : does all css and js files have been donwload? Yes? Ok run the body.
Thank you

There isn't a lot of information you provided which would help us solve the issue directly, however couple of things...
Make sure all your scripts and styles links are places in the head tags. The HTML page gets rendered in browser Top-Down. I.E. It'll load any files from HEAD tags before the body is reached, same thing if you want your scripts to be loaded after the body is loaded.. just put them at the bottom, before the BODY closing tag.
Using JQuery would be the fastest solution if you wanted to perform some functionality after your page has loaded (I know there isn't a JQuery tag, however thought providing a JQuery answer could be advantageous.
$(document).ready(function()
{
//Document Loaded, Put code you want to execute here.
}

Strange behaviour with Javascript inclusion

Hi I'm experiencing some problems including a javascript file in my html project.
When I include it like this at the end right before the body tag my site does not work correctly.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
</body>
If, however i delete the tag at the end to make it look like this
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"/>
</body>
everything works fine.
And if i include it within the head, it also works, independent of the syntax.
Why does it behave like this?

Do what everybody else has said, regarding the <script src="..."></script>
Use just src="//...", instead of src="https://..." or on non-encrypted pages (http vs https) your visitors will get security warnings for mixing the two protocols
If you have written jQuery code anywhere on the page, prior to actually including the file, you're going to get reference errors, where JS will not be able to find the function ($) you're trying to use.
There is a debugger available if you use Chrome, and press CTRL+SHIFT+J : it will take you to the developer-console, where I'm sure you're going to see all kinds of reference errors.
In Firefox, it would be CTRL+SHIFT+K, in IE it's F12.
This works under the same premise as writing in other languages where you try to use libraries or other classes, but don't actually import them until the bottom of your program.

For browser compatibility, you must use the first form:
<script src="https://..."></script>
with an explicit closing tag </script>. If this is the case where your code is not working, then your real problem lies elsewhere and not in the way you close the tag.

There might be some race condition happening for you... it will be good if you can provide complete code... if you attach that in header ... then your jquery is successfully loades and then executes your body part... if your attaching that in body ... then closure of script is give some issues... try to play while changing your script code placements in you body tag.
</script> closing is compulsory to work in cross browsers
This might help you in ur debugging.

Why do you want to load jquery in the end of your code? If you have some other scripts that need jquery, then they should be loaded after it. So either you put all script tags in head or in the end of body — jquery should be loaded before other files that depend on it.

Where is the best place to put JavaScript/Ajax in a document?

Apologies for the dumb sounding question, but I need the experts to clarify.
Out of the three places to put JavaScript, head, $(document).ready, or body, where would the best place be to put some ajax that uses a lot of $GET functions?
For instance I am using a JavaScript function called execute_send() but I am unsure where the best place to put it would be. Below is the error:
Problem at line 67 character 22: 'execute_send' was used before it was defined.
function execute_send() {
Also how does the placement affect the page loading time?

In general, unless for some reason you need it elsewhere, put all of your JS last in the body. The browser won't continue until it's parsed your JS, so it is nice to let the page load first. See http://developer.yahoo.com/performance/rules.html
As an example of when you might actually want to put JS in the head: You might have some A/B testing code that you want to run before the page even renders - in that case, the code should go in the head, because you really do want it to run as soon as possible.

As #Thom Blake said, in general the best place is at the bottom of the <body> (+1 for that) - but I'll expand on that a bit:
The reason for this is that as the browser loads the page, it has to stop loading and parse the JavaScript when it encounters it. So if you have all your scripts in the <head> for instance, there will be a delay in loading all the content in the <body>
Note that this is a delay in loading - separate from the actual execution of the script. Something like $(document).ready() deals with when the script is executed, not with when it is loaded.
Generally, all this matters because you want a web page to feel as responsive as possible, so a best practice list for JavaScript will usually be along these lines:
Place all your scripts at the bottom of the <body> so that the loading of non-JS resources, such as images, is not delayed.
Combine your scripts into a single file, so that the server has to make fewer requests for resources (you'll see this referred to as "minimizing HTTP requests")
Minify you scripts, to reduce their total size, which speeds up loading times
Put any code reliant on the DOM (eg click handlers, HTML manipulation, etc) inside $(document).ready() (or the equivalent method for the JS library in use on the page).

Same subject : whats-pros-and-cons-putting-javascript-in-head-and-putting-just-before-the-body
In the past, i experienced some jquery problems has it was not 'loader' when initialising .. this is why we decided to insert it in the <head>.
In some situations it's not easy to move scripts to the bottom. If, for example, the script uses document.write to insert part of the page's content, it can't be moved lower in the page. There might also be scoping issues. In many cases, there are ways to workaround these situations.
For the rest of javascripts, all before the closing </body> tag.
To explain the 'Why page will load faster' : It wont.
Browsers are single threaded, so it’s understandable that while a script is executing the browser is unable to start other downloads. But there’s no reason that while the script is downloading the browser can’t start downloading other resources. And that’s exactly what newer browsers, including Internet Explorer 8, Safari 4, and Chrome 2, have done.
The difference is visible has your ressources within the <body> tag will load/show sequencialy. When the browser gets to load <script src=...js> the complete file has to be loader before the browser can fetch another ressource. So, it's an illusion, because the browser will load/di more 'visible' content before 'javascripts'.
To visualise the whole thing : firebug > Net (tab)

As stated before, $(document).ready is not a place. (For jQuery, $(document).ready simply ensures that the DOM is fully loaded (ready to manipulate) before any script is executed.) You would place your JavaScript in the <head> or the <body>.
However, putting all of your JavaScript includes and JavaScripts at the bottom of the <body> section is best for loading performance. "Progressive Rendering" and "Parallel Downloading" are blocked for everything below the scripts. If your scripts are the last thing on the page, you're not blocking anything.
This article explains it in more depth.
Example:
<html>
<head>
<!-- MY HEAD CONTENT - LOAD ALL CSS -->
</head>
<body>
<!-- MY HTML CODE -->
<!-- START javascript -->
<script type="text/javascript" src="/ajax/jquery/jquery-1.6.2.min.js"></script>
<script type="text/javascript" src="/ajax/jquery/plugins/jquery.random_plugin.js"></script>
<script type="text/javascript" src="/includes/some_other_scripts.js"></script>
<script type="text/javascript" language="JavaScript">
//<![CDATA[
$(document).ready(function(){
// my jQuery/JavaScript code
});
//]]>
</script><!-- END javascript -->
</body>
</html>

asp.net 2.0 site and location of <script/> tags causing problems/conflicting

I have no idea how to describe this accurately/intelligently because it seems to be completely impossible, yet there must some reason for it.
I am trying to leverage jquery, jquery-ui, qtip (tooltip for jquery) and highcharts (javascript charting), but for purpose of post I could just as easily been only using jQuery and jQuery-UI.
If I include my <script/> tags at the bottom of my <head/> element I get an error trying to call the .slider() extension to configure my sliders. But if I put the <script/> tags right before the closing of my <body/> element then everything works. To illustrate, the following will not work (obviously some pseudo code below):
<head>
<script jquery.js/>
<script jquery-ui.js/>
</head>
<body>
... html ...
<script type="text/javascript">
$(document).ready(function () {
$(".slider").slider( { .. options .. } );
} )
</script>
... more html *including* the .slider elements
</body>
However, if I move the two jQuery script tags to be right above the </body> closing element things work. When the script tags are in the head element and I debug my application, basically the page does appear to have completely loaded and Visual Studio highlights the line calling the .slider() function saying it doesn't know what slider() is. Looking at the call stack, it appears to be correctly calling it from the document ready function...the mark up all appears to be there as well, making me believe the document truly is ready.
Now I didn't include things that are required by asp.net 1.1/2.0 site in my pseudo code, namely a <form/> element with runat="server' and the use of a <asp:ScriptManager/> tag (we needed that for parsing monetary values from different cultures leveraging Microsoft Ajax). I can't believe they would be causing the problem, but maybe they are. Additionally, asp.net injects several of its own script sections (i.e. for validation, post back, etc.)
Regarding the form tag...all the html and document.ready markup would be inside the form tag, while the script tags are always outside of the form tag (either above it, in the head or below it at the bottom of the body).
Obviously I could leave the script tags at the bottom, and I very well may end up doing that, but I am trying to get a clean 'template site' of which to use when creating new client sites and it just feels wrong that I have a restriction forcing me to put those tags at the bottom of the html. I'm sure our framework code (or maybe asp.net's) is simply inserting something that is causing problems/conflicts with jQuery, but I don't really know how to go about debugging/diagnosing what that problem is. So if anyone has any suggestions I'd greatly appreciate it.

It looks like jQuery 1.3.2 is being loaded by ASP.NET (see your second WebResource.axd). The two library versions are overwriting each other. Thus the reason it works when you load 1.6.2 at the end of the page.

Loading a script in the <body> section

I have a javascript for a specific page that I do not wish to be loaded in my header section. Is it possible to load it in the section of the HTML.
Currently I have all my js code inside the but I want to remove it to a seperate js file that I can load.
I tried using this but it did not work.
<script type="text/javascript" src="<?php echo base_url();?>js/jquery-1.5.1.min.js"></script>
Thanks

Q1 : I have a javascript for a specific page that I do not wish to be loaded in my header section. Is it possible to load it in the section of the HTML.
-Yes you can load javascript any where you want, if writing inline code then make sure you add script tag around your code.
-also you can request files like in body
Q2: Currently I have all my js code inside the but I want to remove it to a seperate js file that I can load.
-- no problem in that, thats even better practice.
Q3 Requesting external file
to request external files you write below written fashion
<script src="http://file_name.js" type="text/javascript"></script>

It's not only possible (ref), it's frequently a good idea.
Putting your scripts as late in the page as possible, which frequently means just before the closing </body> tag, means the browser can parse and display your content before stopping to go download your JavaScript file(s) (if external) and fire up the JavaScript interpreter to run the script (inline or external).
Putting scripts "at the bottom" is a fairly standard recommendation for speeding up the apparent load time of your page.

Yes it is possible. Try and see.
For debugging, hardcode the jquery full path.
It is sometime recommended to load it at the end of the of the body, to make the main content of the page load faster.

Is it possible to load it in the section of the HTML.
Yes.
From the spec:
<!ELEMENT BODY O O (%block;|SCRIPT)+ +(INS|DEL) -- document body -->
SCRIPT is among the elements that may be a child of the BODY elements. Numerous other elements may also have SCRIPT children.
<script type="text/javascript" src="<?php echo base_url();?>js/jquery-1.5.1.min.js"></script>
When I run echo base_url() I get my the hostname of my server. This would result in a URL such as example.comjs/query-1.5.1.min.js. You probably should drop that PHP snippet entirely and just use: src="/js/jquery-1.5.1.min.js" which would resolve to http://example.com/s/query-1.5.1.min.js.

Yahoo engineers recommendation for higher performance is to include your scripts at the end of your HTML, just before </body> tag. Therefore, it's even better.
To see where the problem is, you gotta first make sure that your js file is loading. User Firebug and go to scripts tab. Do you see your script? If not, then something is wrong with your path.

it should work...
Did you try to view the generated source and see if the PHP code indeed generated the right path?
beside that, it is recommended to load jQuery from a CDN such as google's :
https://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js