Question: I wrote a PHP shell script which include queuing jobs in centOS with 'at' command.
The queue jobs may vary in time and contents which means the system need to keep quite a large number of jobs.
The application logic will also be a bit difficult to setup with cronjob.
Is there a limit in number of queue jobs in centOS or is there any alternative way of queuing jobs?

Answer: 
I really like this article:
[A re-introduction to JavaScript](https://developer.mozilla.org/en/A_re-introduction_to_JavaScript)
I would also recommend "Secrets of a JavaScript Ninja" by John Resig. It will be out in July this year and would definitely be an excellent resource.

Else, Douglas Crockford "JavaScript:The good parts" is excellent.