Problem with javascript dates

When incrementing months in JavaScript, the standard methods do not produce the expected result in many cases. You have to extend the Date Object methods to offset months.

JavaScript

dateSt=new Date();
dateSt.setFullYear(2017);
 dateSt.setMonth(8);
 dateSt.setDate(5);
 dateSt.setHours(15);
 dateSt.setMinutes(00);
 dateSt.setSeconds(00);
 alert(dateSt);