How to check a form field?

[PythonistL]

I am a newbie with Javascript and would like to check if a text
provided by a users , during filling in an input field , has digits
only.
Any idea?
Thank you
L

 

[Jeff Paffett]

I am a newbie with Javascript and would like to check if a text
provided by a users , during filling in an input field , has digits
only.
Any idea?
Thank you
L

Something like:

if (isNAN(document.getElementById('myTextField').value))
{
code if not number;
}
else
{
code if is number;
}

 

[Evertjan.]

Jeff Paffett wrote on 15 sep 2006 in comp.lang.javascript:

Something like:

if (isNAN(document.getElementById('myTextField').value))
{
code if not number;
}
else
{
code if is number;
}

"Not a number"
is not the same as
"String has digits only"

Try:

if (/[^\d]/.test(document.getElementById('myTextField').value)) {
code if not number;
} else {
code if is number;
}

 

[Tom Cole]

Jeff Paffett wrote on 15 sep 2006 in comp.lang.javascript:

Something like:

if (isNAN(document.getElementById('myTextField').value))
{
code if not number;
}
else
{
code if is number;
}

"Not a number"
is not the same as
"String has digits only"

Try:

if (/[^\d]/.test(document.getElementById('myTextField').value)) {
code if not number;
} else {
code if is number;
}

If you wanted to prevent anything but digits being accepted while
typing, you could attach a function to the onkeypress event of the
textfield and return false for non-digit keystrokes. This way they
wouldn't show up when typed.

There's an example of the opposite on w3schools.com. I don't know how
clean the code is, but it looks like this:

<script type="text/javascript">
function noNumbers(e)
{
var keynum
var keychar
var numcheck

if(window.event) // IE
{
keynum = e.keyCode
}
else if(e.which) // Netscape/Firefox/Opera
{
keynum = e.which
}
keychar = String.fromCharCode(keynum)
numcheck = /\d/
return numcheck.test(keychar)
}
</script>

<form>
Type some text (numbers not allowed):
<input type="text" onkeypress="return noNumbers(event)" />
</form>

Maybe some more seasoned developers could fix any bad coding.

 

[Evertjan.]

Tom Cole wrote on 15 sep 2006 in comp.lang.javascript:

If you wanted to prevent anything but digits being accepted while
typing, you could attach a function to the onkeypress event of the
textfield and return false for non-digit keystrokes. This way they
wouldn't show up when typed.

I think that it is a bad idea, to have the field not reacting to certain
key presses. It distubs and alienates the user.

[And it was not the OQ]

 

[Dr John Stockton]

JRS: In article <[email protected]>, dated Fri, 15
Sep 2006 13:33:47 remote, seen in Evertjan.

"Not a number"
is not the same as
"String has digits only"

Pereant, inquit, qui ante nos nostra dixerunt.

Try:

if (/[^\d]/.test(document.getElementById('myTextField').value)) {
code if not number;
} else {
code if is number;
}

\D == [^\d]

 

[RobG]

Tom Cole wrote on 15 sep 2006 in comp.lang.javascript:


I think that it is a bad idea, to have the field not reacting to certain
key presses. It distubs and alienates the user.

It is also a very unreliable way to attempt to validate the field
content. - it is much better to look at the actual value of the field
as you suggested

 

[Evertjan.]

Dr John Stockton wrote on 16 sep 2006 in comp.lang.javascript:

JRS: In article <[email protected]>, dated Fri, 15
Sep 2006 13:33:47 remote, seen in Evertjan.


Pereant, inquit, qui ante nos nostra dixerunt.

Dixit Aelius Donatus,
qui distingueri Tiberii Claudii Donati necesse est.

Try:

if (/[^\d]/.test(document.getElementById('myTextField').value)) {
code if not number;
} else {
code if is number;
}

\D == [^\d]

Certe!

\D === [^\d]

 

[Evertjan.]

RobG wrote on 16 sep 2006 in comp.lang.javascript:

It is also a very unreliable way to attempt to validate the field
content. - it is much better to look at the actual value of the field
as you suggested

... which should be done, or at least repeated serverside.