HTML DOM Navigator onLine Property

Last Updated : 14 Jun, 2023

The Navigator onLine property is used for returning a Boolean value which specifies whether a browser is in the online or offline mode.
It is a read-only property which returns true if the browser is in online mode or false if it is in the offline mode.

Syntax:

navigator.onLine

Return Value: A Boolean, indicating whether the browser is in online or offline mode.It returns true if the browser is online, otherwise it returns false

Below program illustrates the Navigator onLine Property :
Checking whether the browser is in the online or offline mode.

HTML

<!DOCTYPE html> 
<html> 
<head> 
    <title> 
      Navigator onLine Property in HTML 
    </title> 
    <style> 
        h1 { 
            color: green; 
        } 
          
        h2 { 
            font-family: Impact; 
        } 
          
        body { 
            text-align: center; 
        } 
    </style> 
</head> 
  
<body> 
    <h1>GeeksforGeeks</h1> 
    <h2>Navigator onLine Property</h2> 
      
<p> 
      For checking the browser's mode,  
      double click the "Check Mode" button:  
    </p> 
  
    <button ondblclick="checkmode()"> 
      Check Mode 
    </button> 
  
    <p id="mode"></p> 
  
    <script> 
        function checkmode() { 
  
            // We use navigator.onLine to check if browser is online 
            var o =  
                "Is the browser in online mode? " + navigator.onLine; 
            document.getElementById("mode").innerHTML = o; 
        } 
    </script> 
</body> 
</html> 