sorry for the simple question, haven't done this in a while. when I use the
following script it keeps displaying the value of "x" like a string. for
example, if I type the number 7 in the prompt, it displays the result as 721
instead of the answer I want which is 28. what am I doing wrong.
hanks -Allen Thompson
<html>
<body>
<script language="javas cript">
var y=window.prompt ();
var x=y+3*7;
document.write( x);
</script>
</body>
</html>
19  2033 
Allen Thompson hu kiteb: sorry for the simple question, haven't done this in a while. when I
use the following script it keeps displaying the value of "x" like a
string. for example, if I type the number 7 in the prompt, it
displays the result as 721 instead of the answer I want which is 28.
what am I doing wrong.
hanks -Allen Thompson
<html>
<body>
<script language="javas cript">
var y=window.prompt ();
var x=y+3*7;
var x = (y * 1) + (3*7);
Unless you force js to recognise a variable as a number, half teh time
it assumes it is text, and teh + operator is both addition and
concatenation.
If I had my way, + would be reserved as addition only, and a separate
operator created for concatenation.
--
--
Fabian
Visit my website often and for long periods! http://www.lajzar.co.uk
"Fabian" <la****@hotmail .com> writes: var x = (y * 1) + (3*7);
Or
var x = Number(y)+3*7
or one of the other ways to convert a string into a number.
The important point is that y contains a string (prompt returns a
string), not a number, and that adding a number to a string will
always convert the number to a second string and concatenate the
strings.
<URL:http://jibbering.com/faq/#FAQ4_21>
Unless you force js to recognise a variable as a number, half teh time
it assumes it is text, and teh + operator is both addition and
concatenation.
It's not *that* bad. Javascript won't assume something half of the time.
It consistently treats strings as strings and numbers as numbers, and
when adding something to a string, it converts the other part to a string
and concatenates.
I would rather say that half of the time, you get away with forgetting
that you have a string containing a numeral, because Javascript converts
it to a number before doing arithmetic operations on it. E.g.,
var y = "42";
var x1 = y * 2; // 84
var x2 = y / 2; // 21
var x3 = y - 37; // 5
var x4 = y + 10; // 4210 - addition doesn't convert arguments to numbers.
In the first four cases, you can safely forget that y contains a string.
It's just that you can't always, so you shouldn't.
If I had my way, + would be reserved as addition only, and a separate
operator created for concatenation.
I wouldn't complain about that. I guess the behavior is stolen from Java,
where + also does concatenation on strings.
/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.'
> when I use the following script it keeps displaying the value of "x" like a string. for
example, if I type the number 7 in the prompt, it displays the result as 721
instead of the answer I want which is 28. what am I doing wrong.
hanks -Allen Thompson
<html>
<body>
<script>
var y=window.prompt ();
var x=y+3*7;
document.write( x);
</script>
</body>
</html>
prompt() returns a string. Before using the '+' operator, you need to convert
the string to a number.
var x = (+y) + 3 * 7; http://www.crockford.com/javascript/survey.html
In article <br************ @ID-174912.news.uni-berlin.de>, Fabian
<la****@hotmail .com> wrote: Allen Thompson hu kiteb:
sorry for the simple question, haven't done this in a while. when I
use the following script it keeps displaying the value of "x" like a
string. for example, if I type the number 7 in the prompt, it
displays the result as 721 instead of the answer I want which is 28.
what am I doing wrong.
hanks -Allen Thompson
<html>
<body>
<script language="javas cript">
var y=window.prompt ();
var x=y+3*7;
var x = (y * 1) + (3*7);
<snip>
Just use var x=+y+3*7;
If the y was at the other end of the formula then
var x=3*7+(+y)
--
Dennis M. Marks
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
JRS: In article <es************ @newsread2.news .atl.earthlink. net>, seen
in news:comp.lang. javascript, Allen Thompson <ge********@min dspring.com>
posted at Sat, 13 Dec 2003 03:12:10 :- sorry for the simple question, haven't done this in a while. when I use the
following script it keeps displaying the value of "x" like a string. for
example, if I type the number 7 in the prompt, it displays the result as 721
instead of the answer I want which is 28. what am I doing wrong.
You basic error lies in omitting to read the newsgroup FAQ.
--
© 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> Jsc maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/Jsc/&c, FAQ topics, links.
Dennis M. Marks wrote: If the y was at the other end of the formula then
var x=3*7+(+y)
JFTR:
var x = 3*7+ +y;
is also possible but more error-catching.
PointedEars
Douglas Crockford wrote: prompt() returns a string.
It returns a string if the user confirms. Otherwise
it returns `null', no matter what has been typed.
PointedEars
Thomas 'PointedEars' Lahn <Po*********@we b.de> writes: Douglas Crockford wrote:
prompt() returns a string.
It returns a string if the user confirms. Otherwise
it returns `null', no matter what has been typed.
That is browser dependent. Opera returns "undefined" , not "null".
Bot IE and Mozilla do return "null".
/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.'
Waaaaay back on 13-Dec-03 11:26:28, Douglas Crockford said this about Re: why math wont work?: following script it keeps displaying the value of "x" like a string. for
example, if I type the number 7 in the prompt, it displays the result as
721 instead of the answer I want which is 28. what am I doing wrong. hanks
-Allen Thompson
<html>
<body>
<script>
var y=window.prompt ();
var x=y+3*7;
document.write( x);
prompt() returns a string. Before using the '+' operator, you need to convert
the string to a number.
var x = (+y) + 3 * 7;
That'll still give the same result, unfortunately. Whatcha need to do is this;
var x = parseInt(y)+3*7 ;
That should work.
-- da****@banana-and-louie.org * dauber.50megs.c om
* ICQ: 28677921 * YIM: dau_ber * AIM: ddaauubbeerr This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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