It’s important to do form validation for obvious reasons. This is an implementation of an email checker that uses php regular expressions, and a little bet if pizzaz with asynchronous javascript and xml, or AJAX.

Here’s the example.

A quick rundown of how this works is:

1. You type in a string
2. You hit submit
3. The data is transfered asynchronously (without refreshing the page) to the server
4. The server checks to see if the email is valid or invalid
5. If it’s valid it tells you so, as well as if it’s not

The guts of the script are here:
if (eregi("^[a-zA-Z0-9_-.+]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-_.]+$",$email)) {
//return confirmation that it worked
}
else {
//return that it didn't work
}


Basically, it checks to see if there’s either a lowercase or uppercase a-z or 0-9 or an underscore, or a dash, or a period before the @ sign ([a-zA-Z0-9_-.+]+@). Then after the @ sign it checks for the same thing except for the period and the underscore up until another dot. After that dot it checks once again for the same charachters as the first set.

Hopefully this helps someone. If you have any questions feel free to email me at “howe -dot- jon -at- gmail -dot- com” and I’ll help you however I can.

Later,
Jon Howe

Since I’ve already been on the topic of doing small beginner PHP tutorials, here’s another one. This one is pretty self explanitory.

You can see it here.

Basically what this does is let you enter a domain or page or whatever and it redirects you to the page. On top of just redirecting you, it logs all of the redirections along with the request date, and requester ip address.

If you have a need for this, you’ll most likely know how to implement it. If not, feel free, as always, to email me (howe -dot- jon -at- gmail -dot- com), and I’d be happy to help you out to the best of my abilities.

Later,
Jon Howe

I’ve been wanting to make a script in PHP that handles downloads for a while. Last night I was bored, so I made one.

DISCLAIMER:
This is a very basic example, but if you have any use for this, I’m sure that you can figure out how to use it. If not, I’ll probably work more with it in the future anyways.

This system works with two PHP files.

If you just want to see the script work, go Here.

From there you can download a sample file and see the source of the scripts.

Now, for how it works…

All that the first script (dl.php) does is display a link to the main download script (which handles the actual download) and sets a session variable for 60 seconds in the future.

Once you click on the link, the main download script (dl2.php) sets another session variable containing the time that the link was clicked.

It checks to see if the time that dl.php was generated no more than 60 seconds later than the link was clicked. If it was later than that the download fails.

Feel free to email me (howe -dot- jon -at- gmail -dot- com) if you have any questions, or requests or whatever, and I’ll do my best to get back to you that day.

Later,
Jon Howe