JavaScript Comments

There are two types of Javascript comments.

Single line comment
Multi line comment

JavaScript Single line Comment

Javascript single-line comment can be done by double forward slashes (//). Javascript can not execute the text that lies between (//) and the end of the line.

Let us add a single-line comment for the developer's hint.

Source Code

          
            // It is single line comment  
document.write("I have learned single line comment.");

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Disabling Javascript Source Code

Let us add a single-line comment for disabling the Javascript statement.

Source Code

          
            var productionCost = 100;
var transportCharge = 200;
var profitAmount = 50;
var productSellingCost = productionCost + transportCharge + profitAmout;
document.write(productSellingCost);
//var distributorAmount = (productSellingCost*0.1);

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Javascript Multi Line Comment

Multi-line comment starts with /* and ends with*/. It is used to add a single line as well multi-line comment.

Multi-line comment is used to provide the developer's code hint:

Source Code

          
            /* It is a multi-line comment that will be used for single as well as multi-line comments. 
The commented line can not be displayed  
 */  
document.write("Learn Javascript multi-line comment");

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Disabling Source Code Using Multi Line

Multi-line comment is also used for disabling unnecessary sources of code.

Source Code

          
            function addNumber(x, y) {
  return x + y;
}
/*
//used to comment unnecessory source code
function basicTest(x,y){
function basicTest(x,y){
if(x>y){
document.write("X is greater than Y.");
}else{
document.write("X is smaller than Y.");
}
}
*/
var result = addNumber(10, 20);
//var testResult = basicTest(15>50); Signle line comment
//document.write(testResult); single line comment
document.write("Summation of two number : " + result);

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