Board Optimization - True Asynchronous Cron Jobs using Javascript [!AJAX]. No more hanging page loads.

How vB's Cron Jobs Work (and the problem with them)
vBulletin has a great, built-in scheduled task system. It relies on an invisible pixel image output on the bottom of the forum pages to run the scheduled tasks (cron jobs). It works like this: When a user visits a page, vB checks to see if there are any pending cron jobs to execute. If there are, the cron image is inserted at the bottom of the page. That image, instead of displaying a real image, actually calls the scheduled task script which first returns the image, then proceeds to execute the scheduled task. This setup can cause the page load to hang, depending on what browser you're using. vB goes to great lengths to send the content-length header, then flush the image data to the browser. This causes some browsers to stop loading the page even though the script isn't finished running (it has to execute the cron job), since the data returned matches the content-length header. However, not all browsers are that smart. Sometimes they sit there with whatever indicator they have spinning, saying the page is still loading, until the scheduled task has finished.

How this product works, and how it fixes the problem
This add-on fixes the problem. How it works:
1. First it checks to see if the user has Javascript enabled. No Javascript means the standard vB cron image is used, so your scheduled tasks keep running.
2. If Javascript is enabled, then a short snippet of Javascript is inserted at the bottom of the page instead of the cron image.
3. What this Javascript does is first wait until the page is completely loaded. After the page is loaded, it ask for the standard vB cron image, which runs your scheduled task. After the image is loaded, it displays it (it's invisible) at the bottom of the page. It's as simple as that.

The advantage of this setup is that the cron image is requested via Javascript after the page is done loading, so that the user doesn't think something is wrong and wonder why the page won't finish loading.

Installation
Import the product XML via the Product Manager. You can enable/disable the product in the JS Cron Image Options group.

Technical Specs
This product adds one plugin which inserts Javascript where the vB cron image used to go. That's it.

History
Version 1.0.0 - Initial Release
Version 1.0.1 - Better compatibility with vBa and other 'portal' scripts. $vbulletin->options['bburl'] is prepended to the cron image URL.

This product doesn't change how cron jobs execute at all, it only requests the cron image (which starts cron job execution) in a different way, so that the user doesn't have forever-loading pages.

If you use this, please click Mark As Installed.

[Analogpoint]

Originally Posted by andrewy3k

I have a question.. is there any way to really tell if this actually improves loading times?.. Anyone actually test to see? And is it a more efficient hack for big boards?

thanks ahead of time

This won't improve loading times. The entire page still has to load, and this mod does not affect that. What it does do is keep the page from appearing to hang when it is "almost" done loading. It appears to hang (in some, not all cases), because the pixel image at the bottom of the page, that calls the cron script doesn't load until the cron script is done running. This mod requests the cron image via JS after the page has been loaded, eliminating the annoying pages that are apparently loaded (visually they are all there), but the loading indicator in the browser says the page is still loading because the cron image is still loading.

[andrewy3k]

hmm, I'm trying to recall if thats ever been noticeable on my board.. if there is hang time maybe half a second to a second max to a point it may not be noticeable.. not sure what I should be looking for .. the only hangtime I notice is loading after $navbar .. but thats just because I have a larger board..

[The Bish]

Good lord man! This has solved an issue I have been having with my board for some time. Where in the hell do I send your Christmas Card too?

[andrewy3k]

Originally Posted by The Bish

Good lord man! This has solved an issue I have been having with my board for some time. Where in the hell do I send your Christmas Card too?

whats that?.. please do share..

[The Bish]

I have been having the page load and then hang for what seemed like 5 seconds. Had members complain that it took upwards of 5 seconds or more at times to load. I have been IMing a few of them and they all say it is loading faster although one person says I have a ton of shit html which could also be an issue. So as far as the load hang goes... the usual complainees seem to think it is working better since the install.

[PoetJA-1975]

Originally Posted by Saviour

Noticeable improvement on page loading time. Much appreciated! Marked Installed...

I agree! Thanx so much to the Author of this fine modification

Jacquii.

[andrewy3k]

Maybe I should try .. see if it makes any difference.. I don't think it will.. but wont hurt

[andrewy3k]

I tried it.. didn't see any noticeable differences.. in both FF and IE

[timothydog76]

Installed this today. Seems cool. I noticed one minor glitch (nitpicking really). If I look in the plugins manager the drop-down box and "Go" button are oriented funny. Is this an issue anyone else is seeing?

Thanks,

[jawatkin]

This is a godsend, seriously. I always hated that delay, it was annoying as ever.... And now... Thank you!!