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In a form I have two text fields. In one of them the user enters a
decimal number and in the other a hexadecimal number. What code can be
used to validate that the entered text is numeric and to produce a
warning when it is not.

Cogito wrote:

> In a form I have two text fields. In one of them the user enters a
> decimal number and in the other a hexadecimal number. What code can be
> used to validate that the entered text is numeric and to produce a
> warning when it is not.

Hi Cogito ,


have a look at parseInt(s, radix)
where s is the string to be parsed and radix is optional, but you should use
it to test for hexadecimal strings.

remember that the function parseInt will return NaN (Not A Number) when the
conversion cannot be done.

Good luck.

Regards,
Erwin Moller

Be careful with parseInt, in IE it have a bug, and for 08 or 09 don't have a
good response. If you can, use parseFloat.

Selrak


"Erwin Moller"
<since_humans_read_this_I_am_spammed_too_much@spam yourself.com> escribió en
el mensaje news:40ed3f03$1$568$...
> Cogito wrote:
>
> > In a form I have two text fields. In one of them the user enters a
> > decimal number and in the other a hexadecimal number. What code can be
> > used to validate that the entered text is numeric and to produce a
> > warning when it is not.
>
> Hi Cogito ,
>
>
> have a look at parseInt(s, radix)
> where s is the string to be parsed and radix is optional, but you should
use
> it to test for hexadecimal strings.
>
> remember that the function parseInt will return NaN (Not A Number) when
the
> conversion cannot be done.
>
> Good luck.
>
> Regards,
> Erwin Moller

Selrak wrote:
> Be careful with parseInt, in IE it have a bug, and for 08 or 09 don't have a
> good response. If you can, use parseFloat.

IE doesn't have a "bug" in parseInt, its a bug in the implementation of
the people using it.

http://www.jibbering.com/faq/#FAQ4_12

--
Randy
Chance Favors The Prepared Mind
comp.lang.javascript FAQ - http://jibbering.com/faq/

JRS: In article <40ed3f03$1$568$>, seen in
news:comp.lang.javascript, Erwin Moller <since_humans_read_this_I_am_spa
> posted at Thu, 8 Jul 2004 14:33:11 :
>Cogito wrote:
>
>> In a form I have two text fields. In one of them the user enters a
>> decimal number and in the other a hexadecimal number. What code can be
>> used to validate that the entered text is numeric and to produce a
>> warning when it is not.

>have a look at parseInt(s, radix)
>where s is the string to be parsed and radix is optional, but you should use
>it to test for hexadecimal strings.

But parseInt(S, 10) will accept "10 bananas", which is not a decimal
number. It also accepts 1.999 as meaning 1.

>remember that the function parseInt will return NaN (Not A Number) when the
>conversion cannot be done.

Input validation is best done with a RegExp; see <URL:http://www.merlyn.
demon.co.uk/js-valid.htm>.

decimal: /^\d+$/
hexadecimal: /^[0-9a-z]+$/i

Use {m,n} where m & n are integers to control the number of digits.

In evaluating the hex string, you may need to prefix it with "0x".

Remember : the aim of the authors of javascript was to attach some
meaning to as many forms of input as possible (dates being a good
example); the aim of the programmer needs to be to ensure that only
unambiguous input of suitable value is accepted, and to interpret it
correctly.

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

Erwin Moller said:
>
>Cogito wrote:
>
>> In a form I have two text fields. In one of them the user enters a
>> decimal number and in the other a hexadecimal number. What code can be
>> used to validate that the entered text is numeric and to produce a
>> warning when it is not.
>
>Hi Cogito ,
>
>
>have a look at parseInt(s, radix)
>where s is the string to be parsed and radix is optional, but you should use
>it to test for hexadecimal strings.
>
>remember that the function parseInt will return NaN (Not A Number) when the
>conversion cannot be done.

That depends on what you consider to be "the conversion".
parseInt("action",16) will quite contentedly convert that
invalid input into the number 172.