How to disable backspace in textbox using JavaScript | Example code

Use onkeydown property and block key of backspace “8” or key “Backspace” to prevent users from using the backspace key in a textbox using JavaScript.

Note: This sounds creating a major usability issue if the user makes a typo.

Example disable backspace in textbox in JavaScript

HTML example code. Prevent backspace click via JavaScript by catching onKeyDown and returning false if ascii code is 8 (backspace).

<!DOCTYPE html>

    function isValidKey(e)
      var charCode = e.keyCode || e.which;
      if (charCode == 8){

        return false;
      return true;


  <input id="tb_box" onkeydown="return isValidKey(event)" type="text" />



disable backspace in textbox using JavaScript

Do comment if you have any doubts and suggestion on this JS example code.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.

OS: Windows 10

Code: HTML 5 Version

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.