//-------------------------------------
	// 親のセレクト要素に連動させる
	var select_sync_parent =function (elm_id, parent_elm_id, pair) {
		/*
			<select name="c[Comment.parent]" id="_parent_elm_id">
				<option value="">--</option>
				<option value="1">1</option>
				<option value="2">2</option>
			</select>
			<select name="c[Comment.someitem]" id="_elm_id">
				<option value="">--</option>
				<option value="C121">C121</option>
				<option value="C122">C122</option>
				<option value="C111">C111</option>
				<option value="C112">C112</option>
			</select>
			<script>
				select_sync_parent(
						'_elm_id',
						'_elm_category_id',
						{"C121":"1", "C122":"1","C111":"2", "C112":"2"});
			</script>
		*/
		$(function(){
			values ={};
			$("#"+elm_id+" option").each(function(){
				values[$(this).attr("value")] =$(this).text();
			});
			$("#"+parent_elm_id).bind("change",function(){
				window.elm =window.document.getElementById(elm_id);
				var parent_item_id =$("#"+parent_elm_id).val();
				var counter =0;
				for (var index in elm.options) {
					elm.options[index] =null;
				}
				for (var item_id in values) {
					if (item_id == "" || parent_item_id == pair[item_id]) {
						elm.options[counter++] =new Option(values[item_id],item_id);
					}
				}
			});
			$("#"+parent_elm_id).trigger("change");
		});
	};