Delayed execution of JavaScript code

[Alexander Obuhovich]

To optimize page load times on website Google recommends to postpone JavaScript code execution until it's really needed on a page and to move most (all if possible) of JavaScript code at footer of webpage.

This way loading of external javascript files won't affect page load speed.

Usually, in In-Portal, we put JavaScript code, that is used to process given piece of HTML right after it. This way we keep all in one place, but it's against modern Google approach I've described above.

I'm proposing to create a means to allow placing JavaScript right after relevant HTML piece in TPL file, but at the end make that JavaScript available at the end of a page, where it really belongs.

Usually I would use $(document).ready(...) construct to do this, but since even jQuery itself is loaded at page bottom this becomes impossible.

For example we can use existing tags to arrange this or create new tag just for that. Here is how I see it.

--- CODE ON THE PAGE ---

some html here

<inp2:m_Queue queue_name="...">

<script>

// some javascript here

</script>

</inp2:m_Queue>

some other html on the page

--- CODE IN FOOTER ---

<script>

$(document).ready(function () {

<inp2:m_Queue queue_name="..." minify_as="js"/>

});

</script>

Some explanations:

• Parameter queue_name in example above is optional and allows to have several queues on one page.
• Parameter minify_as tells how queued data should be minified. When omitted no minification happens.
• Tag <script> is added inside just to keep IDE auto-complete working, otherwise whole JS code would be highlighted as big HTML error.
• All <script ...> and </script> tags would be stripped from the result to create one unified block.
• Each m_Queue pair tag can be interpreted as sort-of <inp2:m_Capture to_var=""> ... </inp2:m_Capture> that appends new data to already queued data.
• Each m_Queue non-pair tag can be interpreted as <inp2:m_Param.../> tag to get data from that parameter.

Hope you can see potential of m_Queue tag, since it allows to put absolutely anything into queue for later usage while keeping related data in same place in template.

--
Best Regards,

http://www.in-portal.com
http://www.alex-time.com

[Phil]

Really interesting idea, I support it !

Why we couldn't just move all JS stuff from header to footer?

[Alexander Obuhovich]

If we move all stuff to footer, then when time comes to figure out how stuff works or change it we need to make changes in 2 places instead of one. When TPL file is large scrolling through it to make changes becomes painful task.

[Dmitry A.]

Yes, I agree with Alex - it's not always easier/cleaner just move all JS to the footer - it can get really messy as we recently saw happen with new Intechnic.com website.

Alex, would you please create a new task in In-Portal 5.3.x describing what ideas (very clever way of doing it).

Cheers!

DA

[Alexander Obuhovich]

Here is a task: http://tracker.in-portal.org/view.php?id=1397