how to disable dropdown on chenage on other dropdownvalue

how to disable dropdown on chenage on other dropdownvalue

Hi all,
greetings,
as i am new in jquery. i want to avoid post back while selecting on country.
i have two dropdown one is country and another is state

if i select country other than india state dropdown should be disable.
plz help

My code is:
 <script type="text/javascript">
    $(function(){
    $('#<%=cmbCountry.ClientID %>').click(function(e){
    var ddlstate= $('#<%= cmbState.ClientID%>');
    if(this.checked=='india')
    {
    ddlstate.attr('disabled', true);
    }
    else{
    ddlstate.removeAttr('disabled');
    }
    
    
    });
    });
    
    </script>