Function: Verifies that an email is valid.

Function: Converts email addresses characters to HTML entities to block spam bots.

Function: Converts plaintext URI to HTML links.

Function: Converts text equivalent of smilies to images.

Function: Add leading zeros when necessary.

Function: Adds backslashes before letters and before a number at the start of a string.

Function: Adds slashes to a string or recursively adds slashes to strings within an array.

Function: Converts lone & characters into `&` (a.k.a. `&`)

Function: Balances tags if forced to, or if the ‘use_balanceTags’ option is set to true.