jQuery DatePicker with today as maxDate

http://api.jqueryui.com/datepicker/#option-maxDate

$( ".selector" ).datepicker( "option", "maxDate", '+0m +0w' );

$(".datepicker").datepicker({maxDate: '0'});

This will set the maxDate to +0 days from the current date (i.e. today). See:

http://api.jqueryui.com/datepicker/#option-maxDate