[Cialug] Javascript help

[Kevin C. Smith]

> Kevin C. Smith wrote:
>> I'm trying to come up with a javascript function to check an html form
>> input field. I've got most of it but I'm have trouble with the number
>> after
>> the ".". I'm trying to match number in the form of 12.0, 12.5, 12.00,
>> 12.25, 12.50, 12.75 for example. I've got the following:
>
>    This is from memory, so may be subtly or even completely wrong...
>
>    Try something like:
> 	pattern = /((^[0-2][0-3])|(^[0-1]?[0-9]))\.[0-9]{1,2}$/;
>
>    Should allow 0.0 to 23.99 inclusive.  0.1 to 24.0 would use much the
> same technique.
>
>    Or are you just wanting the specific "xx.0, xx.5, xx.00, etc" as you
> have listed above?  Maybe I'm being dense, but it's hard to tell exactly
> what you have in mind here.
>
>  > [...]Please use proper format - 1:15 PM is 13.25[...]
>  > [...]The range is 0.25-24.0[...]
>
>    I don't know what you are attempting to actually do here and maybe it
> makes perfect sense in the context you are using it in, but something
> like this would cause me untold grief in phone calls from confused users
> and exasperated help desk operators.
>
>    This is just my opinion, so take it with a large grain of salt.  If
> you are expecting an end user to enter a time (or anything else,
> really).  Pick a format that will make sense to them and then convert it
> to whatever you need on the back end.
>
>    Twenty-four hour format is probably acceptable (but not ideal),
> hundredths of an hour is probably stretching things a little much
> depending on your audience.  Even with a geek audience, I would expect a
> lot of bad data that looks like hundredths, but were actually entered as
> minutes. Actually, scratch that, I don't think geeks would get it right
> either...
>
>    In other words, if there needs to be a conversion from minutes to
> hundredths of an hour, accept the time in minutes and multiply by 1.6+7,
> use a lookup table or whatever you need to do behind the scenes.  If you
> need it converted to hundredths and only accept to the nearest quarter
> hour, accept the full range and round it according to whatever rules you
> have to abide by.
>
>    Last resort, add (a) dropdown(s) with just the values you will allow.
>   This is last resort because it introduces a potential maintenance
> nightmare that nobody wants to deal with and can also lead to additional
> UI issues that are preferable not to have to deal with.  There are, of
> course, techniques that help avoid these problems, but I'd prefer to
> just avoid the whole thing if possible.  Not a religious issue, just KISS.
>
>    It's a lot easier for you to do it once than expect everyone who uses
> your form to do it again and again.  As a bonus, you'll have less
> problems with users entering syntactically correct, but factually wrong
> data.
>
>    Not to mention that _when_ the rules change, you won't have to
> (re)train everyone to use a new interface, just change some stuff that's
> transparent to them.
>
>    Now, having said all that...  We've all been in the situation where
> this sort of thing is not possible due to circumstances outside of our
> control so please don't take my comments on this as second guessing or
> mean spirited in any way whatsoever.
>
> HTH,
> Tad Anhalt

I am actually replicating a system already in use on paper, and everyone
already knows the expected format. So, above stuff not an issue really.
I just want to give the users immediate feedback if they mistyped
something. The backend does error checking also. I thought javascript would
be nice for providing immediate feedback, but I never used it before.

FYI, it is in fact time. People enter 13.5 for 1:30 PM, 13.25 for 1:15 PM,
etc. It's time measured in quarter hours. It's how we bill and report
hours.


-- 
Kevin C. Smith