- JavaScript Basics
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- JS var Vs let Vs const
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- JS Loops
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- JavaScript Popup Boxes
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- JavaScript Arrays
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- JS map()
- JavaScript Strings
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- JS Convert to Lowercase
- JS Convert to Uppercase
- JS String Concatenation
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- JS search() Vs. indexOf()
- JS match()
- JS match() Vs. search()
- JS replace()
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- JS String()
- JS includes()
- JS substr()
- JS Slice String
- JS charAt()
- JS repeat()
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- JS charCodeAt()
- JS fromCharCode()
- JS startsWith()
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- JavaScript Objects
- JS Objects
- JS Boolean Object
- JavaScript Math/Number
- JS Math Object
- JS Math.abs()
- JS Math.max()
- JS Math.min()
- JS Math.pow()
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- JS Math.cbrt()
- JS Math.round()
- JS Math.ceil()
- JS Math.floor()
- JS Math.trunc
- JS toFixed()
- JS toPrecision()
- JS Math.random()
- JS Math.sign()
- JS Number.isInteger()
- JS NaN
- JS Number()
- JS parseInt()
- JS parseFloat()
- JavaScript Date and Time
- JS Date and Time
- JS Date()
- JS getFullYear()
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- JS getSeconds()
- JS getMilliseconds()
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- JS getUTCHours()
- JS getUTCMinutes()
- JS getUTCSeconds()
- JS getUTCMilliseconds()
- JS toDateString()
- JS toLocaleDateString()
- JS toLocaleTimeString()
- JS toLocaleString()
- JS toUTCString()
- JS getTimezoneOffset()
- JS toISOString()
- JavaScript Browser Objects
- JS Browser Objects
- JS Window Object
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- JavaScript Regular Expression
- JS Regular Expression
- JS RegEx .
- JS RegEx \w and \W
- JS RegEx \d and \D
- JS RegEx \s and \S
- JS RegEx \b and \B
- JS RegEx \0
- JS RegEx \n
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- JS RegEx \xdd
- JS RegEx Quantifiers
- JS RegEx test()
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- JavaScript Advance
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- JS Form Validation
- JS Validations
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- JS try-catch throw finally
- JS onerror Event
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- JS innerHTML
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- JS getElementsByName()
- JS getElementsByTagName()
- JS querySelector()
- JS querySelectorAll()
- JS document.write()
- JS console.log()
- JS instanceof
- JavaScript Programs
- JavaScript Programs
JavaScript Comments
The word comment refers to a written remark or opinion about any thing. And in computer programming world, a comment is a piece of text placed within a program, that helps other programmer to understand the program.
The comments are ignored while executing the program. Therefore, comments are often helpful while debugging the code.
You can use comment for multiple purposes. For example, use comment to:
- explain some block of code
- explain particular statement
- avoid executing some statement or block of code
- debug the code
- etc.
Types of Comments in JavaScript
There are two types of comments, JavaScript allows. That are:
- Single line comment
- Multi-line comment
Single Line Comment in JavaScript
A single line comment in JavaScript, starts with //. That is, anything written after the // on the same line, will be treated as a comment. For example:
<!DOCTYPE html> <html> <body> <script> console.log("One"); // console.log("Two"); console.log("Three"); // console.log("Four"); console.log("Five"); </script> </body> </html>
The snapshot given below shows the sample output produced by above JavaScript example on comments:
Multi-line Comment in JavaScript
Multi-line comment in JavaScript, starts with /* and ends with */. That is, anything between /* and */ will be treated as a comment. For example:
<!DOCTYPE html> <html> <body> <script> console.log("One"); /* console.log("Two"); console.log("Three"); */ console.log("Four"); /* console.log("Five"); */ console.log("Six"); /* console.log("Seven"); console.log("Eight"); */ console.log("Nine"); </script> </body> </html>
The output produced by this example is:
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