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 enter something other than digits?

The field can have decimal points as well.

Answer 1

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 2

Forget regular expressions. JavaScript has a builtin function for this: isNaN():

isNaN(123)           // false isNaN(-1.23)         // false isNaN(5-2)           // false isNaN(0)             // false isNaN("100")         // false isNaN("Hello")       // true isNaN("2005/12/12")  // true 

Just call it like so:

if (isNaN( $("#whatever").val() )) {     // It isn't a number } else {     // It is a number }