Jq实现省市联动（JqDOM操作和遍历）

<script type="text/javascript" src="jquery-3.2.1.js"></script><script>$(function() {var cities = [ [ "西安", "咸陽" ], [ "鄭州", "商丘" ], [ "石家莊", "唐山" ],[ "昆明", "麗江" ] ];var city = $("#city");$("#pro").change(function() {$("#city option:gt(0)").remove();var val = $(this).val();$(cities).each(function(i, n) {if (i == val) {$(n).each(function(j, cit) {  city.append("<option>"+cit+"</option>");})}})})})</script>