JavaScript Regular Expressions

Regular expressions can be used for all text search and text substitution operations.

A regular expression can be a simple character, or a more complex pattern.

When you search for data in text, you can use the search pattern to describe what you want to query.

Grammar:

/pattern/modifiers;

Instance

var Patt =/w3cschool/i

Instance parsing:

/w3cschool/i is a regular expression.

W3cschool is a pattern (for retrieval).

i is a modifier (search is case insensitive).

The search () method uses regular expression instances

Use regular expressions to search for "w3cschool" strings and are not case-sensitive:

var str = "Visit w3cschool";
var n = str.search (/w3cschool/i);

The output is:

6 Using string methods

In JavaScript, regular expressions are typically used in two string methods: Search () and replace ().

The Search () method retrieves the substring specified in the string, or retrieves a substring that matches the regular expression and returns the starting position of the substring.

The Replace () method is used to replace other characters with some characters in a string, or to replace a substring that matches a regular expression.

JavaScript Regular Expressions