How to Remove First Digit from Number in Javascript
In this tutorial, you will learn how to remove first digit from number in javascript. A number is formed by the combination of digits from 0 to 9. For a newbie developer, it can be a bit tricky to remove the first digit from the number.
There are numerous ways to remove the first digit from the number. But first of all, we have to convert a number into a string using toString()
method. A string consists of multiple characters and these characters in a string have a 0-based index. To get the rest of the string after the removal of the first character, we can make use of the substring()
method.
In the following example, we have one global variable that holds a number. Upon click of a button, we will remove the first digit from the number and display the result on the screen. Please have a look over the code example and the steps given below.
HTML & CSS
- We have 3 elements in the HTML file (
div
,button
, andh1
). Thediv
element is just a wrapper for the rest of the elements. - The
innerText
for thebutton
element is“Get”
and for theh1
element, it is“Result”
. - We have done some basic styling using CSS and added the link to our
style.css
stylesheet inside thehead
element. - We have also included our javascript file
script.js
with ascript
tag at the bottom.
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <link rel="stylesheet" href="style.css"> <title>Document</title> </head> <body> <div class="container"> <button>Get</button> <h1>Result</h1> </div> <script src="script.js"></script> </body> </html>
.container { text-align: center; } button { margin-top: 10px; padding: 10px 20px; }
Javascript
- We have selected the
button
element andh1
element using thedocument.querySelector()
method and stored them inbtnGet
andoutput
variables respectively. - We have attached a
click
event listener to thebutton
element. - We have a global variable
num
which holds a number as its value. - In the event handler function, we are calling the
toString()
method and converting the number to a string. Then, we are callingsubstring()
method and passing 1 as a parameter which is the index number of the second digit“5”
. As a result, we will get a new string except for the first character. The new string is then converted into a number usingparseInt()
and stored in theresult
variable. - We are displaying the
result
in theh1
element using theinnerText
property.
let btnGet = document.querySelector("button"); let output = document.querySelector("h1"); let num = 255488; btnGet.addEventListener("click", () => { let result = num.toString().substring(1); output.innerText = parseInt(result); });