Need a Date type function

Hi everybody,
can any one can give me a program in JavaScript  
i have 3 textbox in asp.net  web form where i textbox will be a day 2nd would be a month and 3rd would be a year 
i want to do this function on onblur 
where when  the person enter the year and try to move out of the text box it should validate all the 3rd text box for a not greater than current date and it should validate for leap year if the particular entry is wronf it should focus me to the textbox  and give a error  .