integer checking ?

[mhk]

hi,

is there any function in Javascript to check/validate integer value.
there is parseInt(val) but it only checks first digit.

example : to find error in 123k44

[Randy Webb]

Re: integer checking ?

mhk wrote:[color=blue]
> hi,
>
> is there any function in Javascript to check/validate integer value.
> there is parseInt(val) but it only checks first digit.
>
> example : to find error in 123k44
>[/color]

myVar = "123k44"

if (myVar == +myVar)

lightly tested.

--
Randy
comp.lang.javas cript FAQ - http://jibbering.com/faq

[mhk]

Re: integer checking ?



Randy Webb wrote:
[color=blue]
> mhk wrote:
>[color=green]
>> hi,
>>
>> is there any function in Javascript to check/validate integer value.
>> there is parseInt(val) but it only checks first digit.
>>
>> example : to find error in 123k44
>>[/color]
>
> myVar = "123k44"
>
> if (myVar == +myVar)
>
> lightly tested.
>[/color]
*************** ***************
yes ... looks like its working but what that "+" does ?
Thanks

[RobG]

Re: integer checking ?

Randy Webb wrote:
[...][color=blue][color=green]
>> is there any function in Javascript to check/validate integer value.
>> there is parseInt(val) but it only checks first digit.
>>
>> example : to find error in 123k44
>>[/color]
>
> myVar = "123k44"
>
> if (myVar == +myVar)[/color]

But that will "validate" any number, not just integers.

If the requirement is that the variable only contains digits (that is,
no decimal point or any other character), if:

var isInt = /^\d+$/.test(a)

then isInt will be true only if 'a' contains only digits.

However, 0.2e3 is a valid int (it is equivalent to 200) - is that OK
with the OP? And 5.0 is a valid int too, but will fail the test.

Have a read here:

<URL:http://www.merlyn.demo n.co.uk/js-valid.htm>

and here:

<URL:http://www.jibbering.c om/faq/faq_notes/type_convert.ht ml#tcUserIn>

--
Rob

[Evertjan.]

Re: integer checking ?

mhk wrote on 16 jan 2005 in comp.lang.javas cript:
[color=blue]
> hi,
>
> is there any function in Javascript to check/validate integer value.
> there is parseInt(val) but it only checks first digit.[/color]
[color=blue]
> example : to find error in 123k44[/color]


<script>
if (isInteger('123 k44'))
alert('yes: 123k44')
else
alert('no: 123k44')

if (isInteger('123 e44'))
alert('yes: 123e44')
else
alert('no: 123e44')

if (isInteger('123 .44'))
alert('yes: 123.44')
else
alert('no: 123.44')


function isInteger(n) {
return (!isNaN(n)) && (Math.floor(n)= =n)
}

</script>

--
Evertjan.
The Netherlands.
(Replace all crosses with dots in my emailaddress)

[Richard Cornford]

Re: integer checking ?

Evertjan. wrote:
<snip>[color=blue]
> function isInteger(n) {
> return (!isNaN(n)) && (Math.floor(n)= =n)
> }[/color]
<snip>

As NaN is specified as never equalling NaN and Math.floor(NaN) results
in NaN:-

function isInteger(n){
return (Math.floor(n) == n);
}

- would be simpler.

Richard.

[Dr John Stockton]

Re: integer checking ?

JRS: In article <cse4ah$fpl$1$8 30fa7a5@news.de mon.co.uk>, dated Sun, 16
Jan 2005 16:21:35, seen in news:comp.lang. javascript, Richard Cornford
<Richard@litote s.demon.co.uk> posted :[color=blue]
>Evertjan. wrote:
><snip>[color=green]
>> function isInteger(n) {
>> return (!isNaN(n)) && (Math.floor(n)= =n)
>> }[/color]
><snip>
>
>As NaN is specified as never equalling NaN and Math.floor(NaN) results
>in NaN:-
>
>function isInteger(n){
> return (Math.floor(n) == n);
>}
>
>- would be simpler.[/color]

isInteger("1000 000000000000000 000000000000000 000000000000.3" )
isInteger("9007 199254740993")
isInteger("3e+3 33")
isInteger("3e-333")
isInteger("0xbe ad")

give true.


Before testing for integer, one should first consider what one really
should be testing for; usually, one wants a digit in [1-9] followed by
not too many decimal digits. The OP should use a RegExp.

--
© John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v4.00 MIME. ©
<URL:http://www.merlyn.demo n.co.uk/> TP/BP/Delphi/&c., FAQqy topics & links;
<URL:http://www.merlyn.demo n.co.uk/clpb-faq.txt> RAH Prins : c.l.p.b mFAQ;
<URL:ftp://garbo.uwasa.fi/pc/link/tsfaqp.zip> Timo Salmi's Turbo Pascal FAQ.

[sancha]

Re: integer checking ?

function isAllDigitsint( argvalue) {
argvalue = argvalue.toStri ng();
var validChars = "0123456789 ";
var startFrom = 0;
if (argvalue.subst ring(0, 2) == "0x") {
validChars = "0123456789abcd efABCDEF";
startFrom = 2;
} else if (argvalue.charA t(0) == "0") {
validChars = "01234567";
startFrom = 1;
} else if (argvalue.charA t(0) == "-") {
startFrom = 1;
}

for (var n = startFrom; n < argvalue.length ; n++) {
if (validChars.ind exOf(argvalue.s ubstring(n, n+1))
== -1) return false;
}
return true;



checks to see if all digits are int
parseInt this and u should get ur result
Problem ???
this accepts octal.
and 09 fails .. need to improve the script.
Please help