Check a value is float or int in jquery

Question

I have the following html field, for which i need to check whether the input value is float or int,

<p class="check_int_float" name="float_int" type="text"></p>


$(document).ready(function(){
   $('.check_int_float').focusout(function(){

       var value  = this.value
       if (value is float or value is int)
          {
           // do something
          }      
       else
          {
           alert('Value must be float or int');   
          }  

   });

});

So how to check whether a value is float or int in jquery.

I need to find/check both cases, whether it is a float, or int, because later if the value was float i will use it for some purpose and similarly for int.

possible duplicate of [How to check if a number is float or integer?](http://stackoverflow.com/questions/3885817/how-to-check-if-a-number-is-float-or-integer) — Oliver Tappin, Dec 01 '13 at 11:24

score 14 · Answer 1 · answered Dec 01 '13 at 11:28

14

use typeof to check the type, then value % 1 === 0 to identify the int as bellow,

if(typeof value === 'number'){
   if(value % 1 === 0){
      // int
   } else{
      // float
   }
} else{
   // not a number
}

answered Dec 01 '13 at 11:28

Janith Chinthana

3,792
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Be aware that even though the value's type is 'number' it can still be number as NaN is of the type number – Anders M. Aug 25 '15 at 07:32
@AndersM. Use IsNumeric then. – snowYetis Jan 19 '17 at 21:18
2

what about if a number having zero after decimal, eg. 10.0 it will be considered as float or int ? – Mahak Choudhary Sep 03 '18 at 06:23

score 6 · Answer 2 · answered Dec 01 '13 at 11:28

6

You can use a regular expression

var float= /^\s*(\+|-)?((\d+(\.\d+)?)|(\.\d+))\s*$/;
var a = $(".check_int_float").val();
if (float.test(a)) {
        // do something
    }
    //if it's NOT valid
    else {
   alert('Value must be float or int'); 
    }

answered Dec 01 '13 at 11:28

Mahmoude Elghandour

2,921
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Perfect! @Mahmoude Elghandour – Harsha Mar 03 '21 at 09:09

reto · Answer 3 · 2013-12-01T11:30:43.150

1

You can use a regular expression to determine if the input is satisfying:

// Checks that an input string is a decimal number, with an optional +/- sign   character.
var isDecimal_re = /^\s*(\+|-)?((\d+(\.\d+)?)|(\.\d+))\s*$/;

function isDecimal (s) {
    return String(s).search (isDecimal_re) != -1
}

Keep in mind that the value from the input field is still a string and not a number type yet.

edited Dec 01 '13 at 11:30

answered Dec 01 '13 at 11:25

reto

9,995
5
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52

score 0 · Answer 4 · answered Dec 01 '13 at 11:26

0

I think the best idea would be to check like this ie, to check the remainder when dividing by 1:

function isInt(value) {
    return typeof value === 'Num' && parseFloat(value) == parseInt(value, 10) && !isNaN(value);
 }

answered Dec 01 '13 at 11:26

Rahul Tripathi

168,305
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k in order to check if it was an integer, may be we can also use default `.isNumeric` in jquery, so now need to find if it was a float, also it there any default method like `.isNumeric` in jquery ? – Shiva Krishna Bavandla Dec 01 '13 at 11:28
@shivakrishna:- Yes there is a function .isNumeric in Jquery. http://api.jquery.com/jQuery.isNumeric/ – Rahul Tripathi Dec 01 '13 at 11:30
@rahuli mean to ask, whether there is also for finding a float ? – Shiva Krishna Bavandla Dec 01 '13 at 11:30
You may check for float like this: function isFloat(value) { return value === +value && value !== (value|0); } – Rahul Tripathi Dec 01 '13 at 11:31
@shivakrishna:- Sure, give it a try! – Rahul Tripathi Dec 01 '13 at 11:34
k now, if i enter 0.0 or 1.0, its returning false actually, so my point is a user can also enter the value as 0.0 or 1.0 as the float valuesinstead if 0 or 1 right ? so may be we should able to handle that scenarios too right ? – Shiva Krishna Bavandla Dec 01 '13 at 11:44
@shivakrishna:- How about this function: function isFloat(value){ return value!= "" && !isNaN(value) && Math.round(value) != value; } – Rahul Tripathi Dec 01 '13 at 11:54
also when i tried isFloat(32.56), it returns `true`, but when i tried the same from template like isFloat(value), it is returning false, because it was a string that coming from input field value – Shiva Krishna Bavandla Dec 01 '13 at 13:09
@shivakrishna:- Did you try with the function which I posted in comments above? – Rahul Tripathi Dec 01 '13 at 13:15
yup i tried the function isFloat(value){ return value!= "" && !isNaN(value) && Math.round(value) != value; } – Shiva Krishna Bavandla Dec 01 '13 at 18:54
So if we enter the value as 2.0, 3.0, 4.0 etc., it was returning me false, and when we give 2.1, 3.1,4.1 etc., its returning true, that means it is considering 2.0, 3.0 etc,(that ends with `.0`) also as integer, which i dont want, because user can also be able to enter the value as 0.0, 1.0 etc., and its working except this case actually – Shiva Krishna Bavandla Dec 01 '13 at 18:55

Check a value is float or int in jquery

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