Thursday 23 August 2018

Javascript: comments

Comments are used to document the source code. Comments in javaScript, makes the program more readable. Comments are ignored by JavaScript.

Suppose you written thousand lines of program, with out proper documentation, after some time, for the owner of the application also, it is very difficult to figure out what was written.

Comments solve this problem:
By using comments, you can document your code at the time of writing program. Comments won't affect your program execution. Comments simply document your code.

Javascript support 2 kinds of comments.

a.   Single line comments
b.   Multi line comments

Single line comment :
Single line comments starts with //
// It is a single line comment

Multi Line comment
Multi line comments are encoded in /* */
/* I am a mulltiline comment */

sample.html
<!DOCTYPE html>

<html>
 <head>
  <title>Variables</title>
 </head>
 
 <body>
  <script type="text/javascript">
   /*
    Java script is weakly typed language
    Author: Hari krishna
   */
   var a = 10;
   document.write("Value of a is " + a + "<br />");
   
   a = "Hello World"; // Assigning string
   document.write("Value of a is " + a + "<br />");
   
   a = true; // Assigning boolean
   document.write("Value of a is " + a + "<br />");
   
   a = 10.09; // Assigning number
   document.write("Value of a is " + a + "<br />");
  </script>
 </body>
</html>



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