To add a number of months to a date, first get the month using getMonth() method and add a number of months.
Example
You can try to run the following code to add a number of months
Live Demo
<!DOCTYPE html> <html> <body> <script> var d, e; d = new Date(); document.write(d); e = d.getMonth()+1; document.write("<br>Incremented month = "+e); </script> </body> </html>