Question

164

Disable backspace in textbox via javascript

rated 0 times [ 167] [ 3] / answers: 1 / hits: 33972 / 15 Years ago, mon, december 21, 2009, 12:00:00

I have a textbox which is extended by an Ajax Control Toolkit calendar.

I want to make it so that the user cannot edit the textbox and will have to instead use the calendar extender for input.

I have managed to block all keys except backspace!

This is what I have so far:

<asp:TextBox ID=TextBox1 runat=server onKeyPress=javascript: return false; onKeyDown=javascript: return false; onPaste=javascript: return false; />

How would I also disable backspace within the textbox using javascript?

EDIT

Made an edit since I need a solution in javascript.

EDIT

It turns out that onKeyDown=javascript: return false; DOES work. I have no idea why it wasn't working before. I tried using a new textbox and it blocked backspaces fine. So sorry to everyone who posted an answer hoping to get some rep esp. after I marked it for bounty.

My textboxes now (seem) to block ALL keystrokes and also still work with the calendar extender.

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louiemarvinm

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3 Years ago

answered 15 Years ago jennie · Accepted Answer

ZX12R was close. This is the correct solution:

The TextBox is like this:

    <asp:TextBox ID=TextBox1 runat=server onKeyDown=preventBackspace();></asp:TextBox>

and the script looks like this:

<script type=text/javascript>

    function preventBackspace(e) {

        var evt = e || window.event;

        if (evt) {

            var keyCode = evt.charCode || evt.keyCode;

            if (keyCode === 8) {

                if (evt.preventDefault) {

                    evt.preventDefault();

                } else {

                    evt.returnValue = false;

                }

            }

        }

    }

</script>

First of all, the backspace wont come through on Key Press, so you have to use Key Down.