Detect if number is INT or FLOAT in jquery

Question

I am currently taking input in a text-box and on-submit, I am validating the input, the input needs to be a number greater than 0, it should be integer and not contain decimal point. The problem is I am not able to find any method by which we can detect it is integer or contains decimal point. Here is the code I am using.

    txt[5] = $(this).parents('p').find('input:text').val();
    if (txt[5] == "" || isNaN(txt[5]) || txt[5] <= 0) 
    {
        alert("Incorrect Quantity");
        return false;
    }

Basically as you see I am validating the input given by user, I want to show them a message if the input is wrong, so I am currently using txt[5]%1!=0 to make sure only INT is allowed, but I am open to new answers.

Why not simply use parseInt()? It truncates floats and 'unparseable' input will return NaN. — Kiruse
– Kiruse, Commented Oct 20, 2013 at 19:12
possible duplicate of How to check if a number is float or integer? — Felix Kling
– Felix Kling, Commented Oct 20, 2013 at 19:13
@FelixKling: Bear in mind that the answer to that dupe will not work if the supplied argument is a string, because typeof "5" is string. — Matt Ellen
– Matt Ellen, Commented Oct 20, 2013 at 19:20
@MattEllen: I don't think it's very difficult to adjust the solution. — Felix Kling
– Felix Kling, Commented Oct 20, 2013 at 19:39

SheetJS · Accepted Answer · 2013-10-20 19:26:27Z

4

The simplest way is to parse the text as a Number, coerce to integer, and see if they are equal:

var numbertxt5 = Number(txt[5]);
if(numbertxt5 | 0 == numbertxt5) { /* int */
} else if (!isNaN(numbertxt5)) { /* float */
} else { /* not a number */

answered Oct 20, 2013 at 19:26

SheetJS

23k12 gold badges68 silver badges76 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Community · Accepted Answer · 2017-05-23 10:27:33Z

3

txt[5] = parseInt($(this).parents('p').find('input:text').val(), 10);

This won't validate the number (see Nirk's answer for that), but if it's not an int, it will be converted to one.

edited May 23, 2017 at 10:27

CommunityBot

11 silver badge

answered Oct 20, 2013 at 19:12

bfavaretto

72k18 gold badges118 silver badges162 bronze badges

9 Comments

Matt Ellen Over a year ago

unless it's not a number

bfavaretto Over a year ago

Yes, that will be trapped by the checks the OP already has in place.

Ankur Over a year ago

What is the "10" at the last?

bfavaretto Over a year ago

It forces the number to be parsed ad a base-10 int. Older browsers interpret numbers starting with zero as octals. @Ankur

bfavaretto Over a year ago

@MattEllen Comma, fixed

|

Huske · Accepted Answer · 2013-10-20 19:28:13Z

3

That is because JavaScript has only one numerical type called number. It is neither int nor float, but it behaves like both at a time. However, you do have two methods that you can use for this parseInt and parseFloat.

var result = parseInt($(this).parents('p').find('input:text').val());
txt[5] = result;

Using parseFloat is similar. Eg.

var result = parseFloat($(this).parents('p').find('input:text').val());
txt[5] = result;

The second example is not what you want but it is here just for your reference.

UPDATE: @bfavaretto made a good point with using radix which I omitted in parseInt. Have a look at this page for reference http://www.w3schools.com/jsref/jsref_parseint.asp

edited Oct 20, 2013 at 19:28

answered Oct 20, 2013 at 19:13

Huske

9,3062 gold badges40 silver badges55 bronze badges

Collectives™ on Stack Overflow

Detect if number is INT or FLOAT in jquery

3 Answers 3

Comments

9 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

9 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related