JSFiddle - React, Tailwind, and code Playground

JavaScript

function ValidateIPaddress(ipaddress)   
{  
 if (/^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/.test(ipaddress))  
  {  
    return (true)  
  }  

    return (false)  
}

alert(ValidateIPaddress("192.138.20.11"))