Date Question

[KL]

I am working on a problem and desperately need help!

I need to prompt a user for the numerical month of birth, day of birth and
year of birth and store it in varialbes and the use the variables to build a
date object. Then print the resulting date object, in it's full form. on
the screen using document.write. This IS for school and I think I am
starting out right, but can't quite seem to grasp what I am doing wrong, or
where to go from here. Any tips would be greatly appreciated.

Here is what I have so far...

<script>
var mob=prompt("Wha t is your month of birth, numerically?", "04");
var dob=prompt("Wha t is the date of your birth, numerically?", "07");
var yob=prompt("Wha t is the year of your birth, numerically?", "1967");
month.setMonth( mob-1);
day.setDate(dob );
year.setFullYea r(yob);
document.write( "Your birthday is " + date + "<br>");
</script>
KL

[Lee]

KL said:

I am working on a problem and desperately need help!

I need to prompt a user for the numerical month of birth, day of birth and
year of birth and store it in varialbes and the use the variables to build a
date object. Then print the resulting date object, in it's full form. on
the screen using document.write. This IS for school and I think I am
starting out right, but can't quite seem to grasp what I am doing wrong, or
where to go from here. Any tips would be greatly appreciated.

Here is what I have so far...

<script>
var mob=prompt("Wha t is your month of birth, numerically?", "04");
var dob=prompt("Wha t is the date of your birth, numerically?", "07");
var yob=prompt("Wha t is the year of your birth, numerically?", "1967");
month.setMonth (mob-1);
day.setDate(do b);
year.setFullYe ar(yob);
document.write ("Your birthday is " + date + "<br>");
</script>

You want to have a single date object, not one each for month, day and year.
The easiest way to do that is to use the form of the Date() constructor that
takes month, day and year as arguments.

var date=new Date(...left for you to find...or ask about...);
document.write( ...as you have it...);

[KL]

"Lee" <RE************ **@cox.net> wrote in message
news:co******** *@drn.newsguy.c om...

KL said:

I am working on a problem and desperately need help!

I need to prompt a user for the numerical month of birth, day of birth and
year of birth and store it in varialbes and the use the variables to build
a
date object. Then print the resulting date object, in it's full form. on
the screen using document.write. This IS for school and I think I am
starting out right, but can't quite seem to grasp what I am doing wrong,
or
where to go from here. Any tips would be greatly appreciated.

Here is what I have so far...

<script>
var mob=prompt("Wha t is your month of birth, numerically?", "04");
var dob=prompt("Wha t is the date of your birth, numerically?", "07");
var yob=prompt("Wha t is the year of your birth, numerically?", "1967");
month.setMont h(mob-1);
day.setDate(d ob);
year.setFullY ear(yob);
document.writ e("Your birthday is " + date + "<br>");
</script>

You want to have a single date object, not one each for month, day and
year.
The easiest way to do that is to use the form of the Date() constructor
that
takes month, day and year as arguments.

var date=new Date(...left for you to find...or ask about...);
document.write( ...as you have it...);

OK I have read and reread this and I think I get some of it. But I am
confused as to what a Date() Constructor is. I don't think we covered that
in class and I don't find it in my book...or I didn't look right..I will
look again, but in the meantime, what can someone tell me about the Date()
Constructor?

KL

[RobG]

KL wrote:
[...]

OK I have read and reread this and I think I get some of it. But I am
confused as to what a Date() Constructor is. I don't think we covered that
in class and I don't find it in my book...or I didn't look right..I will
look again, but in the meantime, what can someone tell me about the Date()
Constructor?

Try the following:

<script type="text/javascript">
var mob=prompt("Wha t is your month of birth, numerically?"," 04");
var dob=prompt("Wha t is the date of your birth, numerically?"," 07");
var yob=prompt("Wha t is the year of your birth, numerically?"," 1967");

var bDay= new Date(yob,mob,do b);
alert(bDay);
</script>
--
Rob

[KL]

"RobG" <rg***@iinet.ne t.auau> wrote in message
news:41******** *************** @per-qv1-newsreader-01.iinet.net.au ...

KL wrote:
[...]

OK I have read and reread this and I think I get some of it. But I am
confused as to what a Date() Constructor is. I don't think we covered
that in class and I don't find it in my book...or I didn't look right..I
will look again, but in the meantime, what can someone tell me about the
Date() Constructor?

Try the following:

<script type="text/javascript">
var mob=prompt("Wha t is your month of birth, numerically?"," 04");
var dob=prompt("Wha t is the date of your birth, numerically?"," 07");
var yob=prompt("Wha t is the year of your birth, numerically?"," 1967");

var bDay= new Date(yob,mob,do b);
alert(bDay);
</script>
--
Rob

Thanks Rob...that helped immensely. I get what I was doing wrong. And best
of all it works now :)

KL

[Dr John Stockton]

JRS: In article <41********@127 .0.0.1>, dated Sat, 27 Nov 2004
23:06:24, seen in news:comp.lang. javascript, KL <kl*******@aohe ll.com>
posted :

"RobG" <rg***@iinet.ne t.auau> wrote in message
news:41******* *************** *@per-qv1-newsreader-01.iinet.net.au ...

KL wrote:
[...]

OK I have read and reread this and I think I get some of it. But I am
confused as to what a Date() Constructor is. I don't think we covered
that in class and I don't find it in my book...or I didn't look right..I
will look again, but in the meantime, what can someone tell me about the
Date() Constructor?

Try the following:

<script type="text/javascript">
var mob=prompt("Wha t is your month of birth, numerically?"," 04");
var dob=prompt("Wha t is the date of your birth, numerically?"," 07");
var yob=prompt("Wha t is the year of your birth, numerically?"," 1967");

var bDay= new Date(yob,mob,do b);
alert(bDay);
</script>
--
Rob

Thanks Rob...that helped immensely. I get what I was doing wrong. And best
of all it works now :)

You saw Rob's omission, then?
Moreover, note that by reading back (two of) the fields from bDay, you
can verify the date as being good Gregorian. Be careful, though, with
historical dates; William Penn's son John "The American", the first by
his second wife, was born on 1700-02-29. See sig 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]

Dr John Stockton wrote:
[..]

Moreover, note that by reading back (two of) the fields from bDay, you
can verify the date as being good Gregorian. Be careful, though, with
historical dates; William Penn's son John "The American", the first by
his second wife, was born on 1700-02-29. See sig below.

Yes, I forgot that. It is certainly an issue as different browsers
support different ranges.

I think the consensus was that since getFullYear() is not always
available, checking that the created date object's date and month were
equal to the input date and month was simplest (provided the OP
remembers to add one to the month...).

--
Rob

[KL]

"RobG" <rg***@iinet.ne t.auau> wrote in message
news:04******** *********@news. optus.net.au...

Dr John Stockton wrote:
[..]

Moreover, note that by reading back (two of) the fields from bDay, you
can verify the date as being good Gregorian. Be careful, though, with
historical dates; William Penn's son John "The American", the first by
his second wife, was born on 1700-02-29. See sig below.

Yes, I forgot that. It is certainly an issue as different browsers
support different ranges.

I think the consensus was that since getFullYear() is not always
available, checking that the created date object's date and month were
equal to the input date and month was simplest (provided the OP
remembers to add one to the month...).

I remembered about the date offset of 1, but I am lost as to the other
issue. Can you really dumb it down for me?

KL
--
Rob

[RobG]

KL wrote:

"RobG" <rg***@iinet.ne t.auau> wrote in message
news:04******** *********@news. optus.net.au...

[...]

Yes, I forgot that. It is certainly an issue as different browsers
support different ranges.

I think the consensus was that since getFullYear() is not always
available, checking that the created date object's date and month were
equal to the input date and month was simplest (provided the OP
remembers to add one to the month...).

I remembered about the date offset of 1, but I am lost as to the other
issue. Can you really dumb it down for me?

When you create a date object using year, month and day you may be
trying to create a date outside the range that the browser can handle.
Since you don't know what browser a user may be using, the easiest way
is to test the date you create against the input you created it from
(assuming you've validated that the input was OK in the first place,
that is that the year is a number, month is between 1 and 12 inclusive
and the day date between 1 and 31 inclusive).

Consider the following function:

function makeDate(y,m,d) {
var theDate = new Date(y,m-1,d);
return theDate;
}

Provided we call it with something like:

alert('The date is ' + makeDate('2003' ,'0','5'));

we should get an alert telling us the date is 5 January, 2003. In some
browsers, (e.g. Safari) if we use:

alert('The date is ' + makeDate('1803' ,'0','5'));

we'll get an error because it can't handle that dates before 1900 or
after 2038 (most other browsers can). So the best way to test is,
after creating our date, to use:

if(theDate.getM onth() != m || theDate.getDate () != d) {
alert('Can't handle date ' + y +'-' + m + '-' + d);
return false;
} else {
return theDate;
}

If you want to be really sure, add: || theDate.getFull Year() != y

However, getFullYear() may not be implemented and rather than messing
around with testing if it is or not, then seeing if the year is less
than 1900 then adding 1900, just don't test the year. The chance that
the month and date will be OK but year incorrect is pretty slim (in
this particular case).

Having said that, if you are going to use getFullYear(), you must test
that the browser supports it first and if not, use some alternative
(say use getYear() and if it returns a value less than 1900, add 1900).

For more fun, follow the link in Dr J's signature:

<URL:http://www.merlyn.demo n.co.uk/js-index.htm> jscr maths, dates,
sources.

--
Rob

[KL]

"RobG" <rg***@iinet.ne t.auau> wrote in message
news:gV******** *********@news. optus.net.au...

KL wrote:

"RobG" <rg***@iinet.ne t.auau> wrote in message
news:04******** *********@news. optus.net.au...

[...]

Yes, I forgot that. It is certainly an issue as different browsers
support different ranges.

I think the consensus was that since getFullYear() is not always
available, checking that the created date object's date and month were
equal to the input date and month was simplest (provided the OP
remembers to add one to the month...).

I remembered about the date offset of 1, but I am lost as to the other
issue. Can you really dumb it down for me?

When you create a date object using year, month and day you may be
trying to create a date outside the range that the browser can handle.
Since you don't know what browser a user may be using, the easiest way
is to test the date you create against the input you created it from
(assuming you've validated that the input was OK in the first place,
that is that the year is a number, month is between 1 and 12 inclusive
and the day date between 1 and 31 inclusive).

Consider the following function:

function makeDate(y,m,d) {
var theDate = new Date(y,m-1,d);
return theDate;
}

Provided we call it with something like:

alert('The date is ' + makeDate('2003' ,'0','5'));

we should get an alert telling us the date is 5 January, 2003. In some
browsers, (e.g. Safari) if we use:

alert('The date is ' + makeDate('1803' ,'0','5'));

we'll get an error because it can't handle that dates before 1900 or
after 2038 (most other browsers can). So the best way to test is,
after creating our date, to use:

if(theDate.getM onth() != m || theDate.getDate () != d) {
alert('Can't handle date ' + y +'-' + m + '-' + d);
return false;
} else {
return theDate;
}

If you want to be really sure, add: || theDate.getFull Year() != y

However, getFullYear() may not be implemented and rather than messing
around with testing if it is or not, then seeing if the year is less
than 1900 then adding 1900, just don't test the year. The chance that
the month and date will be OK but year incorrect is pretty slim (in
this particular case).

Having said that, if you are going to use getFullYear(), you must test
that the browser supports it first and if not, use some alternative
(say use getYear() and if it returns a value less than 1900, add 1900).

For more fun, follow the link in Dr J's signature:

<URL:http://www.merlyn.demo n.co.uk/js-index.htm> jscr maths, dates,
sources.

--
Rob

Thanks for that! I am learning so much!!

KL