Activate Month dropdown only when Year is selected from dropdown in datepicker

Activate Month dropdown only when Year is selected from dropdown in datepicker

Please let me know how to achieve this scenario.

I am using jquery datepicker. now my requirement is that User should only be able to select Year first than Month and than day. this is for Date of birth capturing. Please help me in this.That is becoz users while selecting their DOB are not selecting year of birth which is than taken as default and thus loss of business and revenue