Validating form fields

[Davey]

I want to validate that the data entered by a user is correct before they
submit the form.

How do I validate the following (or what functions/classes do I use):

- Ensure a text field is not empty
- Ensure that a text field contains only numeric values
- Ensure that the contents of a text field is shorter than a certain length
- Remove commas and other formatting from a field before submission

TIA.

[Daniel Kirsch]

Re: Validating form fields

Davey wrote:[color=blue]
> - Ensure a text field is not empty[/color]

if (!yourfield.val ue)
alert("empty")
[color=blue]
> - Ensure that a text field contains only numeric values[/color]

if (yourfield.valu e.search(/\D/) != -1)
alert("only numbers please")

strip all non numeric values:
var val = yourfield.value .replace(/\D/g,"");

[color=blue]
> - Ensure that the contents of a text field is shorter than a certain length[/color]

if (!yourfield.val ue.length > 10)
alert("to long")
[color=blue]
> - Remove commas and other formatting from a field before submission[/color]

removing all of the following characters: ",.-+"
var val = yourfield.value .replace(/[,.\-+]/g,"")
// mask the minus as otherwise it will define a range

Checkout any RegularExpressi on reference of your choice to learn more on
this.

HTH
Daniel

[phal]

Re: Validating form fields


You can use regular expression to do it, it very powerful for user
input validation.

Phal

[RobG]

Re: Validating form fields

Daniel Kirsch wrote:[color=blue]
> Davey wrote:
>[/color]
[...][color=blue][color=green]
>> - Ensure that a text field contains only numeric values[/color]
>
>
> if (yourfield.valu e.search(/\D/) != -1)
> alert("only numbers please")[/color]


if ( /\D/.test(yourfield .value ) )


[...][color=blue][color=green]
>> - Ensure that the contents of a text field is shorter than a certain
>> length[/color]
>
>
> if (!yourfield.val ue.length > 10)
> alert("to long")[/color]

The logic here is back-to-front, it will respond that the text is to
long only if it is not greater than 10.

if ( yourfield.value .length > 10 )
alert("it's too long");


[...]


--
Rob

[Daniel Kirsch]

Re: Validating form fields

RobG wrote:[color=blue]
> Daniel Kirsch wrote:[color=green]
>> if (!yourfield.val ue.length > 10)
>> alert("to long")[/color]
>
>
> The logic here is back-to-front, it will respond that the text is to
> long only if it is not greater than 10.[/color]

Autsch. Another copy&paste bug.

Thanks for correction
Daniel

[Dr John Stockton]

Re: Validating form fields

JRS: In article <4328031d$1_3 @x-privat.org>, dated Wed, 14 Sep 2005
12:06:19, seen in news:microsoft. public.scriptin g.jscript, Davey
<davey@hello.co m> posted :[color=blue]
>I want to validate that the data entered by a user is correct before they
>submit the form.[/color]

You can only do that if you know what it should be, and in that case you
don't need to bother with the form.
[color=blue]
>How do I validate the following (or what functions/classes do I use):
>
>- Ensure a text field is not empty
>- Ensure that a text field contains only numeric values
>- Ensure that the contents of a text field is shorter than a certain length
>- Remove commas and other formatting from a field before submission[/color]

For checks of compliance with a given format, which is not the same
thing as before, see <URL:http://www.merlyn.demo n.co.uk/js-valid.htm>.

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4 ©
<URL:http://www.jibbering.c om/faq/> JL/RC: FAQ of news:comp.lang. javascript
<URL:http://www.merlyn.demo n.co.uk/js-index.htm> jscr maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/jscr/&c, FAQ items, links.

[Stephen Chalmers]

Re: Validating form fields

Davey <davey@hello.co m> wrote in message news:4328031d$1 _3@x-privat.org...[color=blue]
> I want to validate that the data entered by a user is correct before they
> submit the form.
>
> How do I validate the following (or what functions/classes do I use):[/color]

You have to invent your own and there are plenty of tutorials around.
Does your form look anything like this?
[color=blue]
>
> - Ensure a text field is not empty[/color]

Is this a homework assignment.? <input type=text name='hw'>

[color=blue]
> - Ensure that a text field contains only numeric values[/color]

How many days before it's due ? <input type=text name='late'>

[color=blue]
> - Ensure that the contents of a text field is shorter than a certain length[/color]

How do you rate your percentage chances of passing the course? <input type=text name='noChance' >

[color=blue]
> - Remove commas and other formatting from a field before submission[/color]

How much is this course worth to you? <input type=text name='bribe'>

--
S.C.

[Davey]

Re: Validating form fields

"Stephen Chalmers" <ignoring@lycos .co.uk> wrote in message
news:4328c350_2 @mk-nntp-2.news.uk.tisca li.com...[color=blue]
> Davey <davey@hello.co m> wrote in message news:4328031d$1 _3@x-privat.org...[color=green]
>> I want to validate that the data entered by a user is correct before they
>> submit the form.
>>
>> How do I validate the following (or what functions/classes do I use):[/color]
>
> You have to invent your own and there are plenty of tutorials around.
> Does your form look anything like this?
>[color=green]
>>
>> - Ensure a text field is not empty[/color]
>
> Is this a homework assignment.? <input type=text name='hw'>
>
>[color=green]
>> - Ensure that a text field contains only numeric values[/color]
>
> How many days before it's due ? <input type=text name='late'>
>
>[color=green]
>> - Ensure that the contents of a text field is shorter than a certain
>> length[/color]
>
> How do you rate your percentage chances of passing the course? <input
> type=text name='noChance' >
>
>[color=green]
>> - Remove commas and other formatting from a field before submission[/color]
>
> How much is this course worth to you? <input type=text name='bribe'>[/color]

No it looks like this.

Is Stephen Chalmers a wanker?
<select name='ChalmersW anker'>
<option value='1'>Yes</option>
<option value='2'>Defin itely</option>
</select>

[Jan-Christoph Ihrens]

Re: Validating form fields

"Davey" schrieb:
[color=blue]
> I want to validate that the data entered by a user is correct before
> they submit the form.[/color]

If there's a need to validate input for security reasons, do *not* do
this on the client side by using JavaScript. It's just too easy to get
around this. Of course there's nothing to say against an *additional*
client side check, but you shouldn't rely on that.

Greetings,
Jan