RegExp for Date

[zzzxtreme@yahoo.com]

hello i have this function to check date (not mine)


function (s_date) {
// check format
if (!re_dt.test(s_ date))
return false;
// check allowed ranges
if (RegExp.$1 > 31 || RegExp.$2 > 12)
return false;
// check number of day in month
var dt_test = new Date(RegExp.$3, Number(RegExp.$ 2-1), RegExp.$1);
if (dt_test.getMon th() != Number(RegExp.$ 2-1))
return false;
return true;
}


it will check in this format DD-MM-YYYY
is it possible to modify it to be (MM/DD/YYYY OR DD/MM/YYYY) in one
function?

[RobG]

Re: RegExp for Date

zzzxtreme@yahoo .com wrote:[color=blue]
> hello i have this function to check date (not mine)
>
>
> function (s_date) {
> // check format
> if (!re_dt.test(s_ date))
> return false;
> // check allowed ranges
> if (RegExp.$1 > 31 || RegExp.$2 > 12)
> return false;
> // check number of day in month
> var dt_test = new Date(RegExp.$3, Number(RegExp.$ 2-1), RegExp.$1);
> if (dt_test.getMon th() != Number(RegExp.$ 2-1))
> return false;
> return true;
> }
>
>
> it will check in this format DD-MM-YYYY
> is it possible to modify it to be (MM/DD/YYYY OR DD/MM/YYYY) in one
> function?
>[/color]

How are we to know, you haven't shown what the actual regular exression
is. Presumably there is something somwhere that gives 're_dt' a value?




--
RobG

[Dr John Stockton]

Re: RegExp for Date

JRS: In article <1117189072.863 709.15490@o13g2 000cwo.googlegr oups.com>,
dated Fri, 27 May 2005 03:17:52, seen in news:comp.lang. javascript,
zzzxtreme@yahoo .com posted :[color=blue]
>hello i have this function to check date (not mine)
>
>
>function (s_date) {
> // check format
> if (!re_dt.test(s_ date))
> return false;
> // check allowed ranges
> if (RegExp.$1 > 31 || RegExp.$2 > 12)
> return false;
> // check number of day in month
> var dt_test = new Date(RegExp.$3, Number(RegExp.$ 2-1),
>RegExp.$1);
> if (dt_test.getMon th() != Number(RegExp.$ 2-1))
> return false;
> return true;
> }
>
>
>it will check in this format DD-MM-YYYY
>is it possible to modify it to be (MM/DD/YYYY OR DD/MM/YYYY) in one
>function?[/color]

Yes. But neither DMY not MDY is good; YMD is how dates should be,
especially in data.

You should NOT in one input allow either DMY or MDY to be valid. One
can see that 25.12.2004 and 12/25/2005 are a year (and about 5000 miles)
apart - but is 01-07-2006, which is certainly valid, in Winter or in
Summer?

Therefore, your proposed modification would be too unwise to support.


There is no point in checking > 31 and > 12 as such; and you would, if
there were, also need to consider <=0.

The first 'return false' is probably unnecessary; if the final check is
judicious, it will catch soon enough what the first one would. But it
could be made to give a message "that does not even look like a date".

In js-date4.htm#DVal :-


function ValidDate(y, m, d) { // m = 0..11 ; y m d integers, y!=0
with (new Date(y, m, d))
return (getMonth()==m && getDate()==d) /* was y, m */ }


Read the newsgroup FAQ, especially sections 2.3 and 3.2.p (& 4.30).
<FAQENTRY> Could Sec 3.2 become an <ol type=a> list, please </FAQENTRY>
See below.

--
© 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.

[RobG]

Re: RegExp for Date

Dr John Stockton wrote:
[...][color=blue]
> You should NOT in one input allow either DMY or MDY to be valid. One
> can see that 25.12.2004 and 12/25/2005 are a year (and about 5000 miles)
> apart - but is 01-07-2006, which is certainly valid, in Winter or in
> Summer?[/color]

For me at least, 01-07-2006 will be winter (global warming ignored).
It will also likely be winter in that place that persists with M-D-Y
format, but 6 months earlier. :-)

Of course those who share the same hemisphere will disagree.

[...]

--
Rob