checking numeric in javascript

Question

I want to show the 'valid' message if the variable value is

if(isNaN(num) && num !="" && num.length!=10)
{
    alert("invalid");
}
else
{
    alert("valid");
}

But this code shows 'digits which length is not 10' as valid. But whether it is numeric or not numeric, if its length is not 10 it should be invalid.

length is a property valid for string. What do you mean by length here? The number of digits ? — mohkhan
– mohkhan, Commented Jul 2, 2013 at 7:04
number of characters of text box value.. whether it is numeric or alphanumeric — chriz
– chriz, Commented Jul 2, 2013 at 7:07
if you just want to check for the length of string not equal to 10, irrespective of whether it is a number or not, then you just need one check and that is num.length!=10. — bazz
– bazz, Commented Jul 2, 2013 at 7:10
@satinder singh length should not be 10 an it should not be numeric. — chriz
– chriz, Commented Jul 2, 2013 at 7:13

Ruchan · Accepted Answer · 2013-07-02 07:23:45Z

3

Your Condtion placement is wrong here.

isNaN(num) && num !=""
here, for num=1234,isNaN is false(that means it is number), but the num!="" will give true resulting in Invalid alert.

Solution replace && with || for OR condtion.

answered Jul 2, 2013 at 7:23

Ruchan

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1 Comment

REPLACE your && with || How did you miss that

Brian · Accepted Answer · 2013-07-02 07:25:38Z

0

Did you mean this:

if(is_nan(num) && num !="" && num.length<10)
{
alert("invalid");
}
else
{
alert("valid");
}

Otherwise if length is <9 or >10, you will get false.

In this case you will alert valid when your num is non-numeric, nun-empty string with length >= 10.

answered Jul 2, 2013 at 7:07

Brian

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