How to check if a value of the input is number or not?

Question

I have this problem here, I want to check if the value of the input is going to be a number or not on keyup. Any help would be appreciated.

 $('input').keyup(function () {
 var check_nm = $('input').val();
 if(check_nm != "123"){
   console.log('not number');
 }else{
   console.log('is number');
 }
});

jsfiddle

philz · Accepted Answer · 2014-11-05T00:33:29.807

2

$('input').keyup(function () {
  var check_nm = $('input').val();
  if (isNaN(check_nm) || check_nm.trim() == "") {
    console.log('not number');
  }else{
    console.log('is number');
   }
});

Use a combination of isNaN and.trim() == "" to ensure that blank spaces are not counted as numbers

You can also use isNaN(parseFloat(check_nm)) or $.isNumeric(a), which basically runs isNaN(parseFloat())

edited Nov 05 '14 at 00:33

answered Nov 05 '14 at 00:26

philz

982
5
11

This is a correct answer. isNaN should work. – chuysbz Nov 05 '14 at 00:27
@jesusbet Blank spaces fail the isNaN test, so you have to do the "" condition. Try isNaN(" ") in your browser to verify – philz Nov 05 '14 at 00:29
Nice and easy, thanks for your answer. – 7537247 Nov 05 '14 at 16:46
@PhilipA yeah, that's whay I say your answer is the correct answer. – chuysbz Nov 06 '14 at 16:29

score 0 · Answer 2 · answered Nov 05 '14 at 00:26

0

you can check if the number is NOT a number by calling isNaN(num) so if you want the opposite it will be !isNaN()

answered Nov 05 '14 at 00:26

Steve

11,116
7
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score 0 · Answer 3 · edited May 23 '17 at 11:55

You can use unary operator + to convert the value to a number. And then check if it's NaN:

$('input').on('keyup', function () {
    var check_nm = +this.value;
    console.log(isNaN(check_nm) ? 'not number' : 'is number');
});

Note whitespaces and empty string will be converted to 0, so they will be considered a number. If you don't want that, see https://stackoverflow.com/a/1830844/1529630.

score 0 · Answer 4 · edited May 23 '17 at 10:33

0

Use jQuery's $.isNumeric().

Docs @ jquery.com and cool discussion @ SO

edited May 23 '17 at 10:33

Community

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answered Nov 05 '14 at 00:31

CmajSmith

409
2
8

How to check if a value of the input is number or not?

4 Answers4