JavaScript实现省市联动过程中bug的解决方法

$.ajax({
 'type' : 'POST',
 'dataType' : 'json',
 'url' : '${rc.contextPath}/crm/merchantMgr/editMerchantBankAount.htm?method=getBankProvinces',
 'suess' : function(msg) {
  bankProvinces = msg;
  for(var i=0;i<bankProvinces.length;i++){
  $("#key_DSGAprovince").append("<option value='"+bankProvinces[i][0]+"'>"+bankProvinces[i][0]+"</option>");
  }
  
 },
 'cache' : false,
 'async' : false
 });

function getBankCitys(){
$("#key_DSGAcity").empty();
 var DSGAprovince=$("#key_DSGAprovince option:selected").text();
 $.ajax({
 'type':'POST',
 'data': {"province":DSGAprovince}, 
 'dataType': 'json',
 'url':'${rc.contextPath}/crm/merchantMgr/editMerchantBankAount.htm?method=getBankCities',
 'suess' : function(msg) {
  cities = msg;
  for(var i=0;i<cities.length;i++){
  $("#key_DSGAcity").append("<option value='"+cities[i][0]+"'>"+cities[i][0]+"</option>");

  }
 },

 });
}

 var tVal = '海南省';
 if(tVal!=""){$("#key_DSGAprovince").val(tVal);}
 
 var tVal = '文昌';
 if(tVal!=""){$("#key_DSGAcity").val(tVal);} 

var DSGAprovince = '${myObj.DSGAprovince?default("请选择")}';

 $.ajax({
 'type':'POST',
 'data': {"province":DSGAprovince}, 
 'dataType': 'json',
 'url':'${rc.contextPath}/crm/merchantMgr/editMerchantBankAount.htm?method=getBankCities',
 'suess' : function(msg) {
  cities = msg;
  for(var i=0;i<cities.length;i++){
  $("#key_DSGAcity").append("<option value='"+cities[i][0]+"'>"+cities[i][0]+"</option>");
  }
 },
 'cache':false,
 'async':false,
 });