jQuery省市区街道四级联动菜单基于jquery.citys.js制作，二级、三级、四级多种联动菜单示例，扩展显示行政区划第四级(街道)信息，有调用方法，options参数等中文注释。(The four level linkage menu of jQuery province's urban street is based on jquery.citys.js production, two level, three level and four levels of multiple lin