Skip to main content

How to test if a number or string is an integer in javascript

I want to test if a number or a string is an integer or not. Even for the number like 1.00 is actually an integer.

The javascript function to test it:

function IsInt(value)
{
     return (!(isNaN(value) || isNaN(parseInt(value))) && parseFloat(value) === parseInt(value));
}

In Javascript, isNaN method will return false for empty string, i.e., isNaN("") === false. However, parseInt("") will return NaN.

!(isNaN(value) || isNaN(parseInt(value)) will make sure the value is actually a number (it could be an integer or float). The next part parseFloat(value) === parseInt(value) will make sure the value is an integer type.

Here are some test results:

IsInt("") returns false
IsInt("123abc") returns false
IsInt("abc123") returns false
IsInt("1.0") returns true
IsInt(1) returns true
IsInt(1.2) returns false

Take a look at this live demo on jsbin.

Comments

Post a Comment

Popular posts from this blog

Manage IIS 7 remotely using PowerShell and AppCmd

We can use  Windows PowerShell remoting features  to manage IIS 7 websites remotely.  Currently, remoting is supported on Windows Vista with Service Pack 1 or later, Windows 7, Windows Server 2008, and Windows Server 2008 Release 2.  Start Windows PowerShell as an administrator by right-clicking the Windows PowerShell shortcut and selecting Run As Administrator .  Enable PowerShell Remoting with Enable-PSRemoting -Force Starting a Remote Session using:  Enter-PSSession -ComputerName <COMPUTER> -Credential <USER> Now the PowerShell connected to the remote server. Any commands issued with work against the remote server. We can use the Appcmd.exe command line tool to manage remote server just as what we do locally. For example, to add an application pool: c:\windows\system32\inetsrv\appcmd add apppool /name:"Contoso" /managedPipelineMode:Integrated /managedRuntimeVersion:"v4.0" /enable32BitAppOnWin64:true To change application pool for a
Post a Comment
Read more

Entity framework code first error: OriginalValues cannot be used for entities in the Added state

When I was using Entity framework code first, I encountered an error when I tried to create an entity into database. The entity is: [ Table (" EmployeeProfile ")]     public partial class EmployeeProfile     {         [ Key ]         [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]         public int EmployeeProfileID { get; set; }         [ ForeignKey ("Employee")]         public int EmployeeID { get; set; }         public virtual Employee Employee { get; set; }         [ ForeignKey (" Profile ")]         public int ProfileID { get; set; }         public virtual Profile Profile { get; set; }         [ Required ]         [ StringLength (255)]         public string ProfileValue { get; set; }     } When creating the entity, some entities have the ProfileValue="", this causes the EntityValidationException with the detailed message " OriginalValues cannot be used for entities in the Added state ". I want to allow the Prof
Post a Comment
Read more

X509Certificate2: The system cannot find the file specified.

When I use the new X509Certificate2(fileName, password, X509KeyStorageFlags.DefaultKeySet) to create certificate from certificate file containing private key in my web application, I got following error message: System . Security . Cryptography . CryptographicException : The system cannot find the file specified . at System . Security . Cryptography . CryptographicException . ThrowCryptogaphicException ( Int32 hr ) at System . Security . Cryptography . X509Certificates . X509Utils . _LoadCertFromBlob ( Byte [] rawData , IntPtr password , UInt32 dwFlags , Boolean persistKeySet , SafeCertContextHandle & pCertCtx ) at System . Security . Cryptography . X509Certificates . X509Certificate . LoadCertificateFromBlob ( Byte [] rawData , Object password , X509KeyStorageFlags keyStorageFlags ) at System . Security . Cryptography . X509Certificates . X509Certificate2 .. ctor ( Byte [] rawData , String password , X509KeyStorageFlags keyStorageFlags ) In orde
10 comments
Read more