This is as close to a perfect URL regular expression as I've come. It's based on RFC 3986.

A few caveats:

It only accepts http/https/ftp URLs by design, but you could change that to accept any valid URI pretty easily.

It doesn't support IP-based URLs or authenticated URLs. This is also by design, but you could change that with a little work.

This is a simple script to generate a random alphanumeric string.

This is a random password generator that produces understandable passwords based on word lists. I've only included a 3 entry world list because you should chose a list based on your password requirements and your users. If you need to generate passwords that are 14 characters in length, you will want a different list than if you're generating 8 character passwords. And depending on your users, you may want to use certain lists. The list I use is about 4000 words that are 5-7 characters long, all well-known words that have had potentially objectionable content removed. For security reasons I don't want to include this list.

A note on security: though this generates relatively strong passwords for the average user, they are particularly susceptible to brute-force attacks. This is even more an issue if somehow your word list gets compromised. I would not recommend using this function for anything where a highly secure password is needed.

A note on choosing your list: You'll also see that I've built the system to avoid generating passwords with zeros and ones in them. This is because zero and upper-case "o" can be confused as can one, lower-case "L" and upper-case "i." When choosing my word list I was also sure to strip out all words that start with the letter "o" or "i" (to prevent the optional ucfirst() from creating 0/O and I/1 confusion) and words that contain the letter "L" (to prevent l/1 confusion). I find that this greatly helps with preventing confusion, but again weakens the security of the passwords some. It's your choice.

This function creates relatively secure random passwords. It's by no means ideal, but it should work in most non-critical situations. The nice thing is the generator attempts to create passwords that people can pronounce and chooses letters that won't be mistaken for others (such as the numeral "1", an upper-case "i" and a lower-case "L"). To keep the code short much of this functionality is very rudimentary, but it's better than nothing.

This function converts a CSV file to a simple XML file.

This is a bare-bones DB connectivity class. It's really just meant to abstract a few basic mysql_ functions so that if you ever have to change DBs you don't have to change every database function call.

I really just threw this together on a whim with no testing what-so-ever. Also, it only abstracts the most basic MySQL functions--this is intentional; please expand it as you see fit.

Here's a basic function for debugging any kind of PHP variable. It allows for "invisible" or "visible" output--that is output in HTML comments or within visible HTML tags. It also supports customizable "containers" which lets you easily edit the look of the visible and invisible blocks. Examples in code below.