To add months to a JavaScript Date, use the setMonth() method. JavaScript date setMonth() method sets the months for a specified date according to local time.
Example
You can try to run the following code to add 2 months.
<html> <head> <title>JavaScript setMonth Method</title> </head> <body> <script> var dt = new Date("August 20, 2017 11:30:25"); dt.setMonth( dt.getMonth() + 2 ); document.write( dt ); </script> </body> </html>