Formatting strings

[Nige]

I'm a complete novice to JS. I want to insert the date and time into a
document in the format:

WB-MMDDHHmm

Where:

WB- is a fixed string prefix (the whole string is a reference number)
MM is the month 01 to 12, with a leading 0 if required
DD is the day 01 to 31, with a leading 0 if required
HH is the hour 00 to 23, with a leading 0 if required
mm is the minute 00 to 59, with a leading 0 if required
I've got this far:
<script language="JavaS cript">

function ShowDateTime()
{
var today = new Date();
var mo=today.getMon th()+1;
var da=today.getDat e();
var ho=today.getHou rs();
var mi=today.getMin utes();

# parse here #

document.write( "WB-"+mo+da+ho+ mi);
}

</script>
The problem is the bit to parse the strings, I've tried

if (mo.length < 2) mo="0"+mo; ... etc

but it doesn't work.

Help!
--
Nige

Please replace YYYY with the current year
ille quis mortem cum maximus ludos, vincat

[Dr John Stockton]

JRS: In article <71************ *************** *****@4ax.com>, seen in
news:comp.lang. javascript, Nige <uY***@ntlworld .com> posted at Thu, 6
Nov 2003 16:29:26 :-

function ShowDateTime()
{
var today = new Date();
var mo=today.getMon th()+1;
var da=today.getDat e();
var ho=today.getHou rs();
var mi=today.getMin utes();

# parse here #

document.write( "WB-"+mo+da+ho+ mi);
The problem is the bit to parse the strings,

Perhaps you have not read _all_ that the FAQ has to say; see signature
below.

You do not want to parse them, but to format them

function LZ(x) {return(x<0||x> 9?"":"0")+x} // add leading 0

document.write( "WB-" + LZ(mo) + LZ(da) + LZ(ho) + LZ(mi));
--
© 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.

[Thomas 'PointedEars' Lahn]

HikksNotAtHome wrote:

I have no problem with it. I dont recieve the mails (If I do, they get
deleted), so I fail to see how Usenet is a "private" place. As I said, don't
try to email someone, no problems. Trying to get outside of the public Usenet
into private Email is crossing a boundary that I don't care to cross. It opens
up too many problems. If the "Netiquette " says its ok, I don't care, I don't do
it and I won't do it.

*PLONK*

[Thomas 'PointedEars' Lahn]

Nige wrote:

In comp.lang.javas cript, Thomas 'PointedEars' Lahn wrote:

You should never use client-side data when server-side data
is more reliable.
Time zones don't enter into it, all users are in the UK.

I wonder how you can be sure.
All I really need is a reference number that gives the date and approx
time, it doesn't even have to be unique, but the user must be shown the
same number that I get sent by the CGI.
Why, you don't need JavaScript for this (unless your CGI application uses
server-side JavaScript.) Let the CGI application generate the reference
number. Here is it in PHP (untested):

<input type="text" value="<?php
echo date('mdHi', time());
?>">
As I said in my other post (which I sent without giving full details,
sorry), I can't send the CGI data to the next page.
Could you please explain why you assume this is the case?
So the simple option (assuming it is simple) is the generate a string
on the form page, send it with the CGI data, and display it on the
following page.
I think the problem is that we mean different things by "CGI data".
However, as written before, use

<input type="hidden" value="">

and manipulate the value on submit. But the user will then not *see* what
the reference number is, at least not in the form, since it is generated
on submit and not on form generation/display. If you want to the latter
*and* a client-side solution, you need to write the `input' element
dynamically, while using `text' for the value of its `type' attribute:

<script type="text/javascript" language="JavaS cript">
<!--
function getReferenceNum ber()
{
var
d = new Date(),
iMonth = d.getMonth() + 1,
iDay = d.getDay(),
iHours = d.getHours(),
iMins = d.getMinutes();

return (
(iMonth < 10 ? "0" : "") + iMonth
+ (iDay < 10 ? "0" : "") + iDay
+ (iHours < 10 ? "0" : "") + iHours
+ (iMins < 10 ? "0" : "") + iMins)
}

document.write(
'<input type="text" value="' + getReferenceNum ber() + '">');
//-->
</script>

The use of document.write( ...) depends on the document type: In XHTML,
AFAIK you are required to use the W3C-DOM, with its
document.getEle ment...By...(.. .) and HTMLElement.app endChild(...) methods,
instead.

You could also fill the `input' element onload of the `body' element, giving
it a name and referencing it with document.forms[...].elements[...]'. But
users without JavaScript will then see an empty `input' element if you do
not specify otherwise.
Can it be done?

Yes, but if you choose the client-side solution and the users (customers?)
have their JavaScript disabled or no JavaScript support at all, you will
get no (useful) reference number at all. Dependence upon client-side
JavaScript is a Bad Thing, unless we are talking about an Intranet with
client-side conditions under your control or documents that cannot be
reached other than with JavaScript support (which can be evil[tm], too!)
HTH

PointedEars

[Nige]

In comp.lang.javas cript, Thomas 'PointedEars' Lahn wrote:

Time zones don't enter into it, all users are in the UK.

I wonder how you can be sure.

Because it is a campaign site for broadband in Kent.

As I said in my other post (which I sent without giving full details,
sorry), I can't send the CGI data to the next page.

Could you please explain why you assume this is the case?

I've since discovered that I *can* send the date to the page, by
following the url with a ? then the server created date string.

My only problem now is how to extract this from the document.locati on
property (it is there). I've tried code the parse the string to write
the last 8 digits, and code to find the "?" and write the remainder.

I think I need to have a break!
--
Nige

Please replace YYYY with the current year
ille quis mortem cum maximus ludos, vincat

[Nige]

In comp.lang.javas cript, Nige wrote:

My only problem now is how to extract this from the document.locati on
property (it is there). I've tried code the parse the string to write
the last 8 digits, and code to find the "?" and write the remainder.

I think I need to have a break!

Cracked it! My JS book (O'Reilly) implies that window.location returns a
string, but it doesn't!
--
Nige

Please replace YYYY with the current year
ille quis mortem cum maximus ludos, vincat

[Thomas 'PointedEars' Lahn]

Nige wrote:

In comp.lang.javas cript, Thomas 'PointedEars' Lahn wrote:

As I said in my other post (which I sent without giving full details,
sorry), I can't send the CGI data to the next page.Could you please explain why you assume this is the case?

I've since discovered that I *can* send the date to the page, by
following the url with a ? then the server created date string.

Yes, that is called a HTTP GET request which
is also the default for submitting a form.
My only problem now is how to extract this from the document.locati on
property (it is there). I've tried code the parse the string to write
the last 8 digits, and code to find the "?" and write the remainder.

That has nothing to do with CGI as you have told before!
However, I have written a prototype that can be useful here:

http://pointedears.de.vu/scripts/search.htm

Note that the documentation is a bit out of date (see the source code in the
..js file.) `TValue' was changed to `Value', `TSearchStr' to `SearchString',
and enhanced.js is now deprecated; use string.js instead. (Please also
excuse that I wrote `class' in the comments in those days -- it'll be
changed :-)).
PointedEars

[Thomas 'PointedEars' Lahn]

Nige wrote:

Cracked it! My JS book (O'Reilly) implies that window.location returns a
string, but it doesn't!

(window.)locati on is in recent user agents a string value *and* an
object with properties like `href', `protocol', `path', `hash' aso.

Here, in Mozilla/5.0 rv:1.5 and IE 6.0 SP-1, it is. Which user-agent
are you testing with?
PointedEars

[Lasse Reichstein Nielsen]

Thomas 'PointedEars' Lahn <Po*********@we b.de> writes:

(window.)locati on is in recent user agents a string value *and* an
object with properties like `href', `protocol', `path', `hash' aso. Here, in Mozilla/5.0 rv:1.5 and IE 6.0 SP-1, it is. Which user-agent
are you testing with?

In my IE6, it is only an object. It doesn't have the methods from
String.prototyp e (e.g., charAt), and its typeof is "object".

If you convert it to a string, either with String(location ),
location.toStri ng() or ""+location , the resulting string contains
the URL, but that just means that it can be converted to a string.

There is some magic to the location object, though, since *assigning*
to it will really assign to location.href.

As a curiosity, in Opera 7 the location.valueO f method is the same
as the location.toStri ng.

/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[Thomas 'PointedEars' Lahn]

Lasse Reichstein Nielsen wrote:

Thomas 'PointedEars' Lahn <Po*********@we b.de> writes:

(window.)locati on is in recent user agents a string value *and* an
object with properties like `href', `protocol', `path', `hash' aso.

Here, in Mozilla/5.0 rv:1.5 and IE 6.0 SP-1, it is. Which user-agent
are you testing with?

In my IE6, it is only an object. It doesn't have the methods from
String.prototyp e (e.g., charAt), and its typeof is "object".

You're right, the same goes for my UAs. What I meant was that
it returns also a URI string (due to its toString() method) in
the right context.

In contrast, in older UAs like Opera 6 (IIRC), `location' stores
only a primitive string value.
If you convert it to a string, either with String(location ),
location.toStri ng() or ""+location , the resulting string contains
the URL, but that just means that it can be converted to a string.
ACK
There is some magic to the location object, though, since *assigning*
to it will really assign to location.href.
There is no magic involved :) See
http://devedge.netscape.com/library/.../location.html

As a curiosity, in Opera 7 the location.valueO f method is the same
as the location.toStri ng.

Same in Mozilla/5.0 and IE 6.0 SP-1, as expected.
PointedEars

[Lasse Reichstein Nielsen]

Thomas 'PointedEars' Lahn <Po*********@we b.de> writes:

In contrast, in older UAs like Opera 6 (IIRC), `location' stores
only a primitive string value.

YRI (You Remember Incorrectly :)
In Opera 4, 5 and 6, location is an object. I don't have Opera 3 installed,
and Opera 2 doesn't support Javascript.

The same goes for Netscape 4 and 3. You have to go back to Netscape 2
to find a location property that is a plain string.

There is some magic to the location object, though, since *assigning*
to it will really assign to location.href.

There is no magic involved :) See
http://devedge.netscape.com/library/.../location.html

Tha qualified as "magic" to me (something that depends on internal
code and cannot be implemented by a Javscript programmer, like the
array length property [1]).

It says:
---
If you assign a string to the location property of an object,
JavaScript creates a location object and assigns that string to its
href property.
---
That is not correct for *any* object. The following gives me "string":
---
var x = {}; // or var x=document.body ;
x.location = "foo";
typeof x.location
---
So, it is only for window objects, not any object.

As a curiosity, in Opera 7 the location.valueO f method is the same
as the location.toStri ng.

Same in Mozilla/5.0 and IE 6.0 SP-1, as expected.

In my IE 6, the location object doesn't have a valueOf property.
What I mean is that in Opera is the *exact* same function, it doesn't
just give the same result. That is:
location.toStri ng == location.valueO f
and
location.valueO f.toString()
gives
---
function toString() {
[native code]
}
---

/L
[1] I know Netscape 4 and Mozilla have ways to make getters and setters
for properties, but that is not portable Javascript.
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'