Is there an option to restrict the pass dates and say dates after few months in Date picker in VF Page?

Requirement is like a User shouldn't take an Order/Opportunity of past dates and not which belongs to another fiscal month like, For example if a user is saving an Opportunity today he shouldn't save it with past date or August or later month in Close Date.

I tried using jquery as below, But it didnt work. Please let me know if I am making any mistakes.


        <apex:page standardController="Contact">
      <head lang="en">
          <meta charset="utf-8"/>
          <meta name="viewport" content="width=device-width,initial-scale=1.0"/>
          <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
      </head>
      <body>
          <apex:form >
              <apex:pageBlock>
              <apex:pageblockSection>
              <apex:inputField id="output1" value="{!Contact.Birthdate}"/>
              </apex:pageblockSection>
              </apex:pageBlock>
          </apex:form>
          <script>
              $("#datepicker").datepicker({ maxDate: new Date, minDate: new Date(2016, 8, 8) });
              alert('Hello, jQuery');
          </script>
      </body>
    </apex:page>