New Document
var s1 = ["apple","tea"];
var s2 = {apple:["苹果","香蕉"],tea:["龙井","大红袍"]};
$(function(){
$.each(s1, function(){
$("#sa").append(""+this+"");
});
$("#sa").change(function(){
$("#sb").empty();
$.each(s2[$("#sa").val()], function(){
$("#sb").append(""+this+"");
});
});
//手动触发一次onchange
$("#sa").trigger("change");
});
