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, Jul 02 '13 at 07:04
number of characters of text box value.. whether it is numeric or alphanumeric — chriz, Jul 02 '13 at 07:07
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, Jul 02 '13 at 07:10
@satinder singh length should not be 10 an it should not be numeric. — chriz, Jul 02 '13 at 07:13
@chriz: ok in your case you want lengh shud be less or greater then 10 is valid but not equal to 10 — Satinder singh, Jul 02 '13 at 07:15
@bazz i don't want any alphabets in my string.. assume i am trying to take a mobile number.. it's length should be 10 and it should be numeric also.. so it should show valid only in this case.. — chriz, Jul 02 '13 at 07:19
to check if numeric you can see that question http://stackoverflow.com/questions/18082/validate-numbers-in-javascript-isnumeric — thinklinux, Jul 02 '13 at 07:21
@chriz: in prev above comment you said `@satinder singh length should not be 10 an it should not be numeric` and now `@bazz i don't want any alphabets in my string.` Pls clear you question WHAT YOU WANT ?? — Satinder singh, Jul 02 '13 at 07:22
ok.. i know that its working alone but when i add it with length property in condition, not showing expected result.. — chriz, Jul 02 '13 at 07:23

score 3 · Accepted Answer · answered Jul 02 '13 at 07:23

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 02 '13 at 07:23

Ruchan

1

REPLACE your `&& with || ` How did you miss that – Ruchan Jul 02 '13 at 07:27

Brian · Answer 2 · 2013-07-02T07:25:38.333

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.

edited Jul 02 '13 at 07:25

answered Jul 02 '13 at 07:07

Brian

2 Answers2