How to print a number with commas as thousands separators in JavaScript?

Method 1: Using Intl.NumberFormat()

• The Intl.NumberFormat() object is used to represent numbers in language-sensitive formatting. It can be used to represent currency or percentages according to the locale specified.
• The locales parameter of this object is used to specify the format of the number. The 'en-US' locale is used to specify that the locale takes the format of the United States and the English language, where numbers are represented with a comma between the thousands.
• The format() method of this object can be used to return a string of the number in the specified locale and formatting options. This will format the number with commas at the thousands of places and return a string with the formatted number.

Syntax:

nfObject = new Intl.NumberFormat('en-US') nfObject.format(givenNumber)

Example: 

<h1 style="color: green"> GeeksforGeeks </h1> <b> How to print a number with commas as thousands separators in JavaScript? </b> <p>Output for '123456789': <span class="output"></span> </p> <button onclick="separateNumber()">Separate thousands</button> <script type="text/javascript">  function separateNumber() {  givenNumber = 123456789;    nfObject = new Intl.NumberFormat('en-US');  output = nfObject.format(givenNumber);    document.querySelector('.output').textContent = output;    } </script> 

Output:

Method 2: Using toLocaleString()

• The toLocaleString() method is used to return a string with a language-sensitive representation of a number. The optional locales parameter is used to specify the format of the number.
• The locale 'en-US' is used to specify that the locale takes the format of the United States and the English language, where numbers are represented with a comma between the thousands. This will format the number with commas at the thousands of places and return a string with the formatted number.

Syntax:

givenNumber.toLocaleString('en-US')

Example: 

<h1 style="color: green">GeeksforGeeks</h1> <b> How to print a number with commas as thousands separators in JavaScript? </b> <p>Output for '987654321': <span class="output"></span> </p> <button onclick="separateNumber()"> Separate thousands </button> <script type="text/javascript">  function separateNumber() {  givenNumber = 987654321;    output = givenNumber.toLocaleString('en-US');    document.querySelector('.output').textContent = output;    } </script> 

Output: