/**
 * JS联动菜单工具,适用于code形式的树型类别,如code:10001000 父code:1000
 * 示例：
 * var selector=new hb.util.Selector({
 *         url:"/path/to/main/seletor/resources",
 *         assistUrl:"/path/to/assist/selector/resources",
 *         changeCallback:function(){
 *             alert("alert while selector change")
 *         },
 *         field:{code:"code",label:"name"}