checking if number entered is a digit in jquery

Question

I have a simple textbox in which users enter number.
Does jQuery have a isDigit function that will allow me to show an alert box if users ente

Answer 1

var yourfield = $('fieldname').val();

if($.isNumeric(yourfield)) { 
        console.log('IM A NUMBER');
} else { 
        console.log('not a number');
}

JQUERY DOCS:

https://api.jquery.com/jQuery.isNumeric/

Answer 2

With jQuery's validation plugin you could do something like this, assuming that the form is called form and the value to validate is called nrInput

$("form").validate({
            errorElement: "div",
            errorClass: "error-highlight",
            onblur: true,
            onsubmit: true,
            focusInvalid: true,
            rules:{
                'nrInput': {
                    number: true,
                    required: true
                }
            });

This also handles decimal values.

Answer 3

there is a simpler way of checking if a variable is an integer. you can use $.isNumeric() function. e.g.

$.isNumeric( 10 );     // true

this will return true but if you put a string in place of the 10, you will get false.

I hope this works for you.

Answer 4

I would suggest using regexes:

var intRegex = /^\d+$/;
var floatRegex = /^((\d+(\.\d *)?)|((\d*\.)?\d+))$/;

var str = $('#myTextBox').val();
if(intRegex.test(str) || floatRegex.test(str)) {
   alert('I am a number');
   ...
}

Or with a single regex as per @Platinum Azure's suggestion:

var numberRegex = /^[+-]?\d+(\.\d+)?([eE][+-]?\d+)?$/;
var str = $('#myTextBox').val();
if(numberRegex.test(str)) {
   alert('I am a number');
   ...
}    

Answer 5

jQuery is a set of JavaScript functions, right? So you could use JavaScript's regular expression support to validate the string. You can put this in a jQuery callback if you like, too, since those just take anonymously-declared function bodies and the functions are still JavaScript.

Link: http://www.regular-expressions.info/javascript.html

Answer 6

Following script can be used to check whether value is valid integer or not.

  function myFunction() {
    var a = parseInt("10000000");
    if (!isNaN(a) && a <= 2147483647 && a >= -2147483647){
    alert("is integer"); 
    } else {
     alert("not integer"); 
    }
}