How can I prevent users from using the backspace or delete keys in a textbox using JavaScript?

Question

How can I prevent users from using the backspace or delete keys in a textbox using JavaScript?

I have a text box in my web form. I want to use JavaScript on keypress of the textbox to disable the delete and backspace keys.

Can anyone help?

Answer 1

Here's a bit of code to block the certain key press events - or something along those lines (haven't tested the code).

function isValidKey(e)
{
    var charCode = e.keyCode || e.which;
    if (charCode == 8 || charCode == 46)
        return false;

    return true;
}

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

Answer 2

Why are you letting people edit the contents of the text box but restricting them from being able to use basic editing keys? This sounds like you are creating a major usability issue - what if the user makes a typo?

I'd recommend either setting the readonly flag (if you don't want users to edit the value) or disabled flag (if you don't even want it submitted)