JavaScript string replace() Method (original) (raw)

Last Updated : 26 Jun, 2024

JavaScript **replace() method is used for manipulating strings. It allows you to search for a specific part of a string, called a _substring, and then replace it with another _substring.

What's great is that this method _doesn't alter the original string, making it ideal for tasks where you want to maintain the integrity of the original data. Understanding how to use _replace() can enhance your ability to work with strings effectively in JavaScript.

**Syntax:

str.replace(value1, value2);

**Parameters:

• **value1: is the regular expression that is to be replaced
• **value2: is a string that will replace the content of the given string.

**Return Values:

It returns a new string with replaced items.

**Example 1: Below is an example of the string.replace() Method.

javascript `

let string = 'GeeksForGeeks'; let newstring = string.replace('GeeksForGeeks', 'GfG'); console.log(newstring);

`

**Explanation:

• A string string is assigned the value 'GeeksForGeeks'.
• The replace() method is called on string, searching for the substring 'GeeksForGeeks' and replacing it with 'GfG'.
• Since the entire string 'GeeksForGeeks' matches, it is replaced with 'GfG'.
• The new string 'GfG' is assigned to the variable newstring.
• newstring is logged to the console.

**Example 2: Here the contents of the string GeeksForGeeks will be replaced with gfg.

javascript `

// Assigning a string let string = 'GeeksForGeeks is a CS portal';

// Calling replace() method let newstring = string.replace(/GeeksForGeeks/, 'gfg');

// Printing replaced string console.log(newstring);

`

**Explanation:

• A string string is assigned the value 'GeeksForGeeks is a CS portal'.
• The replace() method is called on string, using a regular expression to match the substring 'GeeksForGeeks' and replace it with 'gfg'.
• The first occurrence of 'GeeksForGeeks' in the string is replaced with 'gfg'.
• The modified string is assigned to the variable newstring.
• The replaced string newstring is logged to the console.

**Example 3: Below is an example of the string.replace() Method.

javascript `

// Taking a regular expression let re = /GeeksForGeeks/;

// Taking a string as input let string = 'GeeksForGeeks is a CS portal';

// Calling replace() method to replace // GeeksForGeeks from string with gfg let newstring = string.replace(re, 'gfg');

// Printing new string with replaced items console.log(newstring);

`

**Explanation:

A regular expression re is defined to match the substring 'GeeksForGeeks'.

• A string string is assigned the value 'GeeksForGeeks is a CS portal'.
• The replace() method is called on string, using the regular expression re to match the substring 'GeeksForGeeks' and replace it with 'gfg'.
• The first occurrence of 'GeeksForGeeks' in the string is replaced with 'gfg'.
• The modified string is assigned to the variable newstring.
• The replaced string newstring is logged to the console.

We can also replace the same words at multiple places in a string. It is known as a global replacement.

**Example 4: This example explains replacing of various similar words in a string.

JavaScript `

// Assigning a string let string = 'GeeksForGeeks is a CS portal.' + 'In GeeksForGeeks we can learn multiple languages.' + 'geeksForGeeks is a great place.';

// Calling replace() method let newstring = string.replace(/GeeksForGeeks/g, 'Gfg');

// Printing replaced string console.log(newstring);

`

Output

Gfg is a CS portal.In Gfg we can learn multiple languages.geeksForGeeks is a great place.

**Explanation:

A multi-line string string is assigned with multiple occurrences of the substring 'GeeksForGeeks'.

• The replace() method is called on string, using a regular expression with the global flag (/g) to match all occurrences of the substring 'GeeksForGeeks' case-sensitively and replacing them with 'Gfg'.
• All occurrences of 'GeeksForGeeks' in the string are replaced with 'Gfg'.
• The modified string is assigned to the variable newstring.
• The replaced string newstring is logged to the console.

**Supported Browsers:

• Google Chrome 1 and above
• Edge 12 and above
• Firefox 1 and above
• Opera 4 and above
• Safari 1 and above