• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar

The Programming Expert

Solving All of Your Programming Headaches

  • HTML
  • JavaScript
  • jQuery
  • PHP
  • Python
  • SAS
  • Ruby
  • About
You are here: Home / JavaScript / Using JavaScript to Convert String to Integer

Using JavaScript to Convert String to Integer

September 14, 2022 Leave a Comment

We can use JavaScript to convert a string to an integer by using the JavaScript parseInt() method.

var num = parseInt("20.12345");

The above code would return the number 20.


The parseInt() JavaScript method will parse the value given to it as a string and then return the first Integer in the string. If no integer is found at the start, NaN will be returned.

Some other examples of the parseInt() method are below:

var num1 = parseInt("$11");
var num2 = parseInt("30 40 50");
var num3 = parseInt("The first number is 2 followed by 3");
var num4 = parseInt("10.10 is the first number");
var num5 = parseInt("-10 50");

console.log(num1);
console.log(num2);
console.log(num3);
console.log(num4);
console.log(num5);

#Output
NaN
30
NaN
10
-10

Note the parseInt() JavaScript method is similar to the parseFloat() method, the main difference being that parseInt() will only return the Integer, while parseFloat() will return decimal values as well.

Convert String to Integer using JavaScript

Below we will provide code to let the user input a string, and then use the parseInt() method to return the first Integer. Here is our simple HTML setup:

<p>Type something you want to use the parseInt() method on below:</p>
<input id="userVal" type="text" value="">
<div id="click-me"  onclick="convertStringToInt()">Convert to Integer</div>
<div id="results"></div>

Below is the JavaScript code which takes the user input using an onclick event, and uses the parseInt() method on that user input. We update the results below using the textContent property.

function convertStringToInt(){
  document.getElementById("results").textContent = parseInt(document.getElementById("userVal").value);
};

The final code and output for this example is below:

Code Output:

Type something you want to use the parseInt() method on below:

Convert to Integer

Full Code:

<p>Type something you want to use the parseInt() method on below:</p>
<input id="userVal" type="text" value="">
<div id="click-me"  onclick="convertStringToInt()">Convert to Integer</div>
<div id="results"></div>

<script>

function convertStringToInt(){
  document.getElementById("results").textContent = parseInt(document.getElementById("userVal").value);
};

</script>

Hopefully this article has been useful in helping you understand how to use JavaScript to convert a string to int.

Other Articles You'll Also Like:

  • 1.  Using JavaScript to Remove All Non-Alphanumeric Characters From a String
  • 2.  Using JavaScript to Get the Page Title
  • 3.  setTimeout javascript – How the setTimeout() Method in JavaScript Works
  • 4.  How to Use JavaScript to Change Text in Span
  • 5.  Check if Checkbox is Checked in JavaScript
  • 6.  clearInterval JavaScript – How the clearInterval() Method in JavaScript Works
  • 7.  Add Years to a Date Using JavaScript
  • 8.  How to Check if a String Contains Vowels in JavaScript
  • 9.  Using JavaScript to Add to Array
  • 10.  Using JavaScript to Check If String is a Number

About The Programming Expert

The Programming Expert is a compilation of a programmer’s findings in the world of software development, website creation, and automation of processes.

Programming allows us to create amazing applications which make our work more efficient, repeatable and accurate.

At the end of the day, we want to be able to just push a button and let the code do it’s magic.

You can read more about us on our about page.

Reader Interactions

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Primary Sidebar

About The Programming Expert

the programming expert main image

Welcome to The Programming Expert. We are a group of US-based programming professionals who have helped companies build, maintain, and improve everything from simple websites to large-scale projects.

We built The Programming Expert to help you solve your programming problems with useful coding methods and functions in various programming languages.

Search

Learn Coding from Experts on Udemy

Looking to boost your skills and learn how to become a programming expert?

Check out the links below to view Udemy courses for learning to program in the following languages:

Copyright © 2023 · The Programming Expert · About · Privacy Policy