Numeric value 2

[mitch77]

Hi,
How can I view if a variable has a numeric value using javascript?


Thanks Mitch

 

[luciddream]

if(typeOf(varname) == "Number&quot adam@aauser.com

 

[jaredn]

actually it needs to be a lowercase "n" like:

if(typeOf(varname) == "number&quot jared@aauser.com

 

[luciddream]

yeah yeah, whatever.... adam@aauser.com

 

[palbano]

> How can I view if a variable has a numeric value using javascript?

> yeah yeah, whatever....

> if(typeOf(varname) == "number&quot

hehe, well actually you both missed the mark by a mile unless the original question was mis-stated.

"if a variable has a numeric value"
typeof() tests the type not the value B-)

function ( param){
if ( isNaN(param))
alert("Not a number value"
else
alert("Number value"
}

-pete

 

[iza]

hey pete, i guess that you'll return false for a string which value is, say, "12"
sooooooooooooooo
the very proper way to check that is actually :
if (isNaN(parseInt(param, 10))) and then pete's code
where 10 is for the radix ;-)

 

[jaredn]

x="10"
alert(isNaN(x))

returns true jared@aauser.com

 

[iza]

yes, what i was saying, but alert(isNaN(ParseInt("10", 10)) should be false !!!

 

[jaredn]

no, I meant it returned false jared@aauser.com

 

[iza]

then jscript is clever !!!

 

[jaredn]

yes it dynamically converts between data types and adds wrapper objects when needed... jared@aauser.com

 

[palbano]

Actually parseInt() should return NaN if it cannot obtain a valid number from the string... so it is likely that the functions use the same algorithm. The main difference is that parseInt() allows different radix input where isNaN can only be used directly on base 10, i.e.:

isNaN("B2" // true ( not a number )
isNaN(parseInt("B2", 16)); // false ( is a number)

-pete

 

[jaredn]

that's not true at all:

x="105bxxbxv"
alert(isNaN(x))
x=parseInt(x)
alert(isNaN(x)) jared@aauser.com

 

[luciddream]

no, jared... he's right. look at the example again. adam@aauser.com

 

[jaredn]

they don't function the same at all. their usefulness is similar, but they function much differently jared@aauser.com

 

[palbano]

jaredn,

You are correct. While my example is correct my statement about using the same algorithm was not. Thanks for catching my error.

-pete

 

[jaredn]

no problem mate jared@aauser.com