/**

*    Chained Selects for jQuery 

*    Copyright (C) 2008 Ziadin Givan www.CodeAssembly.com  

*

*    This program is free software: you can redistribute it and/or modify

*    it under the terms of the GNU General Public License as published by

*    the Free Software Foundation, either version 3 of the License, or

*    (at your option) any later version.

*

*    This program is distributed in the hope that it will be useful,

*    but WITHOUT ANY WARRANTY; without even the implied warranty of

*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

*    GNU General Public License for more details.

*

*    You should have received a copy of the GNU General Public License

*    along with this program.  If not, see http://www.gnu.org/licenses/

*

*    

*   settings = { usePost : true, before:function() {}, after: function() {}, default: null, parameters : { parameter1 : 'value1', parameter2 : 'value2'} }	

*   if usePost is true, then the form will use POST to pass the parameters to the target, otherwise will use GET

*   "before" function is called before the ajax request and "after" function is called after the ajax request.

*   If defaultValue is not null then the specified option will be selected.

*   You can specify additional parameters to be sent to the the server in settings.parameters.

*

*/

jQuery.fn.chainSelect = function( target, url, settings ) 

{

  return this.each( function()

  {

	$(this).change( function( ) 

	{

		settings = jQuery.extend(

		{

			after : null,

			before : null,

			usePost : false,

			defaultValue : null,

			parameters : {'_id' : $(this).attr('id'), '_name' : $(this).attr('name')}

        } , settings);

		settings.parameters._value =  $(this).val();

		if (settings.before != null) 

		{

			settings.before( target );

		}

		ajaxCallback = function(data, textStatus) 

		{

			$(target).html("");//clear old options

			data = eval(data);//get json array

			for (i = 0; i < data.length; i++)//iterate over all options

			{

			  for ( key in data[i] )//get key => value

			  {	

					$(target).get(0).add(new Option(data[i][key],[key]), document.all ? i : null);

              }

			}

			if (settings.defaultValue != null)

			{

				$(target).val(settings.defaultValue);//select default value

			} else

			{

				$("option:first", target).attr( "selected", "selected" );//select first option

			}

			if (settings.after != null) 

			{

				settings.after(target);

			}

			$(target).change();//call next chain

		};

		if (settings.usePost == true)

		{

			$.post( url, settings.parameters, ajaxCallback );

		} else

		{

			$.get( url, settings.parameters, ajaxCallback );

		}

	});

  });

};