I was recently (if you are reading this in 2025, assume recently was about 14 or 15 years ago!) developing on a newer version of PHP than what is currently used on most of our servers and I was getting a warning telling me that the function ereg was depreciated.
A little searching told me that is is going to be totally removed from PHP 6 so in the interest of keeping my code nice and up-to-date I made the following changes;
Use preg_match instead of ereg and wrap the expression with //
Here is an example;
ereg("^[-]?[0-9]+([\.][0-9]+)?$", $var);
Becomes
preg_match("/^[-]?[0-9]+([\.][0-9]+)?$/", $var);