Script to Tell Tell Time then Limit by it?

[Mike A]

Hi,
I'm hoping someone can help me with this.

I have a URL for which I'd like to limit access to by time. For
example,say I have a URL that I don't want accessable on Monday mornings
between 10am-noon and Fri. afternoons between 2-4pm. So when someone clicks
on the URL during those times a message pops up saying somthing like "sorry we're
closed now etc"

Is this possible? if yes, I'm guessing I'll need somesort of "onclick" for the
href and a script to check the sys time/date ?

TIA,
Mike

[Michael Winter]

"Mike A" wrote on 15/11/2003:

Hi,
I'm hoping someone can help me with this.

I have a URL for which I'd like to limit access to by time. For
example,say I have a URL that I don't want accessable on Monday
mornings between 10am-noon and Fri. afternoons between 2-4pm. So
when someone clicks on the URL during those times a message pops up
saying somthing like "sorry we're closed now etc"

Is this possible? if yes, I'm guessing I'll need somesort of
"onclick" for the href and a script to check the sys time/date ?

Be aware that it is much better to do this server-side. Many users
routinely disable JavaScript, so your restrictions will be ignored.
However, if your host doesn't allow server-side processing, you might
do something like:

// Returns boolean false if the website
// is closed, true otherwise
// All comparisons are done using UTC (GMT).
function isAccessable()
{
var now = new Date(); // Get current time and date

select( now.getUTCDay() )
{
case 1: // Monday
// Time between 10:00:00 and 11:59:59 UTC
if(( 10 <= now.getUTCHours () ) && ( 12 > now.getUTCHours () ))
return false;
break;
case 5: // Friday
// Time between 14:00:00 and 15:59:59 UTC
if(( 14 <= now.getUTCHours () ) && ( 16 > now.getUTCHours () ))
return false;
break;
}
window.alert(
'Sorry, this site is closed between the following times (GMT):\n'
+ '\n10:00 and 12:00 on Mondays'
+ '\n14:00 and 16:00 on Fridays' );
return true;
}

....and use a link like:

<A href="my-time-restricted-page.html"
onclick="return !isClosed();">E nter</A>

One last point: as I've learnt recently, operations involving dates
can be very tricky. Although you shouldn't have any trouble here (the
comparisons are quite simple in the example above), you might want to
take a look at the 'Date and Time' section of Dr J R Stockton's
JavaScript Index (http://www.merlyn.demon.co.uk/js-index.htm).

Hope that helps,

Mike

--
Michael Winter
M.Winter@[no-spam]blueyonder.co.u k (remove [no-spam] to reply)

[Fabian]

Mike A hu kiteb:

Hi,
I'm hoping someone can help me with this.

I have a URL for which I'd like to limit access to by time. For
example,say I have a URL that I don't want accessable on Monday
mornings
between 10am-noon and Fri. afternoons between 2-4pm. So when someone
clicks
on the URL during those times a message pops up saying somthing like
"sorry we're closed now etc"

Is this possible? if yes, I'm guessing I'll need somesort of
"onclick" for the href and a script to check the sys time/date ?

How do you plan to account for different time zones? How do you plan to
account for computers whose clocks are set incorectly?
--
--
Fabian
Visit my website often and for long periods!
http://www.lajzar.co.uk

[Dr John Stockton]

JRS: In article <15************ **************@ posting.google. com>, seen
in news:comp.lang. javascript, Mike A <mi***@capital. net> posted at Sat,
15 Nov 2003 06:08:49 :-

I have a URL for which I'd like to limit access to by time. For
example,say I have a URL that I don't want accessable on Monday mornings
between 10am-noon and Fri. afternoons between 2-4pm. So when someone clicks
on the URL during those times a message pops up saying somthing like "sorry
we're
closed now etc"

Is this possible? if yes, I'm guessing I'll need somesort of "onclick" for the
href and a script to check the sys time/date ?

Firstly, what do you mean by "Monday"? On the WWW, a day lasts for
about 48 hours, starting at 0000h in or to the Eastward of NZ and
finishing at 2400h somewhere South of the Aleutians.

Probably you mean Monday GMT; or Monday your local time; or Monday in
server's local time; or Monday in some other location; or Monday in your
user's time - and, with all but the first, there is the Summer/Winter
question.

What you ask is, of course, impossible. If I know that URL, I can put
it on a page of my own, and I can click on it at any time I like; even
when I am not connected to the Net. You can, in principle, arrange for
that URL to give a modified 404 response at those times (GMT, server
local, or your local; the user's time is AFAIK unknowable at that
stage). That will need some sort of server-side code.
You can put script in the page itself (which will only work if the user
executes script) to do a pop-up instead of showing the page (unless the
user has a pop-up killer), based on time read from the user's clock and
interpreted as local, or GMT, or elsewhere. The user can defeat this by
setting his clock differently.

You can put the URL on a page of your own, with code such that the click
only works in allowable hours; that's easily defeated

Using user's local time, to determine whether the page should be shown:

T = new Date() // Now
D = T.getDay() // Sun=0..Sat=6
H = T.getHours() // 0..23
Not = D==1 ? H>10 && H<12 : D==5 ? H>14 && H<16 : false
or
HoW = D*24+H
Not = (HoW>34 && HoW<36) || (HoW>134 && HoW<136)

then maybe

if (Not) { DoPoP() ; location.href = ... }

For GMT, use the getUTC functions instead. For remote time, adjust the
UTC to that, see via below.

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4 ©
<URL:http://jibbering.com/faq/> Jim Ley's FAQ for news:comp.lang. javascript
<URL:http://www.merlyn.demo n.co.uk/js-index.htm> JS maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/JS/&c., FAQ topics, links.

[Dr John Stockton]

JRS: In article <JM************ *******@news-text.cableinet. net>, seen
in news:comp.lang. javascript, Michael Winter <M.Winter@[no-spam]> posted
at Sat, 15 Nov 2003 15:39:21 :-

"Mike A" wrote on 15/11/2003:

I have a URL for which I'd like to limit access to by time.

Be aware that it is much better to do this server-side. Many users
routinely disable JavaScript, so your restrictions will be ignored.
It is possible to have a lead-in page which uses javascript to call the
real page provided that the time is right. If the lead-in page appends
the time_t of call to the URL, and the real page checks early in loading
that the present time is no earlier than that and not much later
aborting otherwise, modest security is obtained. The time can be
encoded in Base 36 and shuffled, to make the situation obscure. Non-JS
users then do not see the real page, and cheating is non-trivial.
select( now.getUTCDay() )
I'm not familiar with that use of "select"; I'd use "switch".
// Time between 10:00:00 and 11:59:59 UTC
Not really. Time >=10h & <12h.
if(( 10 <= now.getUTCHours () ) && ( 12 > now.getUTCHours () )) window.alert(
'Sorry, this site is closed between the following times (GMT):\n'
+ '\n10:00 and 12:00 on Mondays'
+ '\n14:00 and 16:00 on Fridays' );
return true;
}

AFAICS, that alert is given when the site is accessible.

On the whole, only tested code is worth posting.

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4 ©
<URL:http://jibbering.com/faq/> Jim Ley's FAQ for news:comp.lang. javascript
<URL:http://www.merlyn.demo n.co.uk/js-index.htm> JS maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/JS/&c., FAQ topics, links.

[Michael Winter]

Dr John Stockton wrote on 16 Nov 2003:

JRS: In article
<JM************ *******@news-text.cableinet. net>, seen in
news:comp.lang. javascript, Michael Winter <M.Winter@[no-spam]>
posted at Sat, 15 Nov 2003 15:39:21 :-

"Mike A" wrote on 15/11/2003:

I have a URL for which I'd like to limit access to by time.

Be aware that it is much better to do this server-side. Many
users routinely disable JavaScript, so your restrictions will be
ignored.

It is possible to have a lead-in page which uses javascript to
call the real page provided that the time is right. If the
lead-in page appends the time_t of call to the URL, and the real
page checks early in loading that the present time is no earlier
than that and not much later aborting otherwise, modest security
is obtained. The time can be encoded in Base 36 and shuffled,
to make the situation obscure. Non-JS users then do not see the
real page, and cheating is non-trivial.

select( now.getUTCDay() )

I'm not familiar with that use of "select"; I'd use "switch".

Simple confusion between languages.
// Time between 10:00:00 and 11:59:59 UTC

Not really. Time >=10h & <12h.

That is, for all intents and purposes, the same thing. If the hour
is, or is after 10, and at any time during the 11th hour, it is as I
described (though more correctly 11:59:59.999) and evaluated below.

if(( 10 <= now.getUTCHours () ) && ( 12 > now.getUTCHours ()
))

window.alert(
'Sorry, this site is closed between the following times
(GMT):\n' + '\n10:00 and 12:00 on Mondays'
+ '\n14:00 and 16:00 on Fridays' );
return true;
}

AFAICS, that alert is given when the site is accessible.

You would be correct. If you check the HTML snippet I included, the
function name is 'isClosed()'. I thought that I'd reverse the logic
to make it easier to use, but I obviously forgot to negate the
comparisons. Each if statement should be corrected to:

if( !( <original expression )) { statements }

Thank you for bringing attention to my lapse in concentration: I've
informed the original poster by e-mail (he contacted me after I made
my post).

Mike

--
Michael Winter
M.Winter@[no-spam]blueyonder.co.u k (remove [no-spam] to reply)

[Michael Winter]

I really did make a pigs ear of my original code: all returns need to
have their values inverted too.

I truly am sorry about this. I will make sure that I review and test
any code in my responses thoroughly. I will refrain from posting
further unless I am as certain as I can be about the validity of the
advice or suggestions I give.

Sincerly,
Michael Winter

[Mike A]

Ok, As a newbie, I'll have to ask as I'm now totally confused.
I'm trying to edit Michael Winter's original code with the edits
he suggested (in a previous post) with no luck, would someone
be kind and assist?

TIA,
Mike

[Michael Winter]

Mike A wrote on 17 Nov 2003:

Ok, As a newbie, I'll have to ask as I'm now totally confused.
I'm trying to edit Michael Winter's original code with the edits
he suggested (in a previous post) with no luck, would someone
be kind and assist?

TIA,
Mike

Unless someone can find any more errors (I did boundary test it) or I
overlooked something, this should be fine (under Opera 7.22 and IE 6,
at least). Any comments relating to date operations are also welcome.
The script:

function isAccessable()
{
var now = new Date(); // Get current time and date

switch( now.getUTCDay() )
{
case 1: // Monday
// Time between 10:00:00 and 11:59:59.999 UTC
if( !(( 10 <= now.getUTCHours () ) && ( now.getUTCHours () < 12 )))
return true;
break;
case 5: // Friday
// Time between 14:00:00 and 15:59:59.999 UTC
if( !(( 14 <= now.getUTCHours () ) && ( now.getUTCHours () < 16 )))
return true;
break;
}
window.alert(
'Sorry, this site is closed between the following times (GMT):\n'
+ '\n10:00 and 12:00 on Mondays'
+ '\n14:00 and 16:00 on Fridays' );
return false;
}
The HTML:

<A href="my-time-dependant-page.html"
onclick="return isAccessable(); ">Enter</A>

I really am sorry about the mix up. Be warned: when entering a month,
remember that they're zero based (0 - January, 1 - February, etc).

Also remember to convert all times to UTC (GMT) so the comparisons
are applicable all over the world.

Mike

--
Michael Winter
M.Winter@[no-spam]blueyonder.co.u k (remove [no-spam] to reply)

[Dr John Stockton]

JRS: In article <15************ **************@ posting.google. com>, seen
in news:comp.lang. javascript, Mike A <mi***@capital. net> posted at Mon,
17 Nov 2003 09:49:58 :-

Ok, As a newbie, I'll have to ask as I'm now totally confused.
I'm trying to edit Michael Winter's original code with the edits
he suggested (in a previous post) with no luck, would someone
be kind and assist?

That may be sub-optimal.

To the article to which the above is a response, add :

or
HoW = D*100 + H
Not = (HoW>110 && HoW<112) || (HoW>514 && HoW<516)

or
HoW = D + H/100
Not = (HoW>1.10 && HoW<1.12) || (HoW>5.14 && HoW<5.16)

Note that the numbers are of the form <Day-of-JS-Week><Hours>; cf.
<URL:http://www.merlyn.demo n.co.uk/js-date1.htm#DC> and
<URL:http://www.merlyn.demo n.co.uk/js-date1.htm#TCp>.

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 IE 4 ©
<URL:http://jibbering.com/faq/> Jim Ley's FAQ for news:comp.lang. javascript
<URL:http://www.merlyn.demo n.co.uk/js-index.htm> JS maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/JS/&c., FAQ topics, links.