2. JavaScript Variables

2.4. Using const


          Much like variables defined using the let statement, constants are block-scoped. The const declaration creates a constant whose scope is often either global or local to the declared block during which we declare it. The value of a constant is read-only; you cannot change it through reassignment, and you cannot redeclare it. An initializer for a constant is required; i.e., you want to specify its value within the same statement in which it is declared (since you cannot alter it later). A function or a variable within the same scope cannot have the same name as the variable.

          Declaring your constants in uppercase is a good practice, because this may help programmers differentiate the constants from other variables within the program.

          Refer to the given example:





  1. <html>
  2.  <body>
  3.      <h2>Use const to declare a variable</h2>
  4.      <script>
  5.          var x = 5;
  6.          const GREETING = "Hi, Pisay </br>";
  7.          document.write(GREETING);
  8.          document.write("The value of variable x is: " + x);
  9.     </script>
  10.  </body>
  11. </html>