Validate a calendar field with a custom javascript code

Hello. I'm trying to perform a verification for my calendar field but my javascript code don't work. I want my field to display an error message when the user put a date greater than today's one.

jQuery.fn.form.settings.rules.verifdatecreation = function(value, param) {

var currentDate = new Date().setHours(0,0,0,0);
var selectedDate = new Date(value);

if (selectedDate > currentDate) {
return false;
}else{
return true;
}
};