# JavaScript Program to Check Leap Year

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## What is Leap Year?

A leap year is a calendar year containing one additional day added to keep the calendar year synchronized with the astronomical or seasonal year. For example, 2024 is a leap year.

Tips: It is recommended to use our online Leap Year calculator for better understanding.

## Condition for Leap Year

To check whether a year is a leap year or not, the year should satisfy at least one of the following two conditions

1. A year should be exactly divisible by 4, but, not by 100.
2. A year should be exactly divisible by 4, 100 and 400 at the same time.

## Check Leap Year

In the following example, we will check whether the given year (2012) is leap year or not.

### Example

HTML Online Editor
<!DOCTYPE html> <html> <body> <h1>JS Leap Year or Not</h1> <script> var year = 2012; if(year % 4 == 0) { if((year % 100 == 0) && (year % 400 != 0)) document.write(year +" is not a leap year"); else document.write(year +" is a leap year"); } else document.write(year+" is not a leap year"); </script> </body> </html>

## Leap Years between the Given Range

In the following example, we will find all the Leap Years between 2000 and 2030.

### Example

HTML Online Editor
<!DOCTYPE html> <html> <body> <h1>JS Find All Leap Years</h1> <script> var start = 2000; var end = 2030; var flag = 0; document.write("Leap year(s) between "+start+" to "+end+":<br>"); for(start = start; start <= end; start++) { if(start % 4 == 0) { if((start % 100 == 0) && (start % 400 != 0)) { //Not a leap year } else { flag = 1; document.write(start+", "); } } } if(flag == 0) document.write("There is no leap year between between the given range"); </script> </body> </html>

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