Backspace keycode is 8 and key is “Backspace”. Pop up Alert box if the user has hit either the backspace key.
Get backspace keycode in JavaScript Example
HTML example code: JavaScript detect backspace
Use event.key == Backspace
Check if the key’s code matches the key code of Backspace.
<!DOCTYPE html>
<html>
<body>
<input type="text" id="txtbox">
<script>
var input = document.getElementById('txtbox');
input.onkeydown = function() {
var key = event.code;
if( key == "Backspace" ){
alert(key);
}
};
</script>
</body>
</html>Use event.keyCode == 8
Check if the key pressed is Backspace keycode.
<!DOCTYPE html>
<html>
<body>
<input type="text" id="txtbox">
<script>
var input = document.getElementById('txtbox');
input.onkeydown = function() {
var key = event.keyCode || event.charCode;
if( key == 8 ){
alert(event.code);
}
};
</script>
</body>
</html>Output:
Another way – addEventListener
<input type="text" id="txtbox">
<script>
var input = document.getElementById('txtbox');
input.addEventListener('keydown', function(event) {
const key = event.key;
if (key === "Backspace") {
alert(key);
}
});
</script>Do comment if you have any doubts and suggestions on this JS keycode topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version