To restrict a text field to accept only numbers using JavaScript, you can use the onkeypress event to validate each key pressed by the user.
For example we write
<input type="text" id="numberField" onkeypress="return isNumberKey(event)">
to an input.
And here’s the JavaScript function to enforce the restriction:
function isNumberKey(evt) {
var charCode = (evt.which) ? evt.which : event.keyCode;
if (charCode > 31 && (charCode < 48 || charCode > 57)) {
return false;
}
return true;
}
In this code, the isNumberKey() function checks if the key pressed is a number.
It uses event.which or event.keyCode to determine the key code of the pressed key.
If the key code is not within the range of numbers (48 to 57 for digits 0-9), it returns false, preventing the input.
This method will ensure that only numeric characters are allowed in the text field.
However, keep in mind that users can still paste non-numeric text into the field unless you additionally handle the onpaste event to prevent this.
