why this coding not run

[new_php85]

haii...i new in js. i want ask why my coding not run. i use php and javascript. this is my sample coding

 

Briefly description: start_date and closing_date retrieve from database and date_me will key in by user

example  start_date=2008-10-02  closing_date=2008-10-11

<script type="text/javascript">
function validDate(me)
{
var prob=false;

if(me.date_me.value=="")
{
	alert("Please enter date");
	prob=true;
}

if(me.date_me.value>me.closing_date.value)
{
	alert("Please enter valid date");
	prob=true;
}

if(me.date_me.value<me.start_date.value)
{
	alert("Please enter valid date. The date are entered already close");

}

if(prob)
{			
	return false;
}

else
{
	return true;
}
}
</script>

 

When user key in date_me>closing_date(2008-10-11)the program is success. then only 2008-10-11 and 2008-10-10 can add by user in database. why below then 2008-10-10(2008-10-9, 2008-10-8 and so on) user still cannot add (error massege appear "Please enter valid date").i thought if date_me>closing_date(2008-10-11), all date below than 2008-10-11 which are 10,9,8,7,6,5 oct 2008 still can add. by why only 10 and 11 october.

 

then for date_me<start_date(2008-10-02) why when i put 2008-09-01 it still can add. suppose error mesage will appear "Please enter valid date".

 

i dont know if i forgot something.can you help me. plzzzzzzzz  ??? ??? ???