A regular expression (regex for short) is a special text string for describing a search pattern. For example you could use the regular expression /^[A-Z0-9._-]+@[A-Z0-9][A-Z0-9.-]{0,61}[A-Z0-9]\.[A-Z.]{2,6}$/i to check if the user entered a properly formatted email address.
If you've got a complicated RegEx you are trying to get right, use this utility to test it.
Example : Following example will search for word php in given string. The "i" after the pattern delimiter indicates a case-insensitive search.
Regular expression - /php/i
String - PHP is the website scripting language of choice.
