In a web page URL, the hostname (i.e. "www.example.com") is either the registered name or IP address assigned to a web page or website (can include a port number as well).

When programming in JavaScript, how do you get the URL hostname and port number of the current page?

JavaScript has a built-in way to get this information using the Location API interface, which represents the location (URL) of the current web page you're located on. The global Window interface has access to the Location object that can be used via window.location.

Here's what the method looks like in practice:

    
      window.location.host
    
  

This will return a string value containing the hostname and, if the port value is non-empty, a : symbol along with the port number of the URL.

Here are some example returned values to expect:

    
      // Page URL: https://coderrocketfuel.com/courses
      window.location.host == "coderrocketfuel.com"

      // Page URL: https://coderrocketfuel.com:80/courses
      window.location.host == "coderrocketfuel.com:80"
      
      // Page URL: http://localhost:3000
      window.location.host == "localhost:3000"
    
  

For more information on the browser support for this method, see its MDN web docs page.

Thanks for reading and happy coding!