php - 如何在设置前一个列表框值时设置选择框或下拉列表框的值

Question

Possible Duplicate:
Use jquery to change second select list based on first select list option

我的代码中有两个选择元素。第一个用于州 (#us_state)，第二个用于城市 (#city_name)。当我选择“州”时，第二个选择元素必须仅包含选定州中存在的城市。

Answer 1

一种可能的解决方案:

var data = {
    "State 1": ["City 1", "City 2"],
    "State 2": ["City 3", "City 4"],
    "State 3": ["City 5", "City 6", "City 7"]
};

var $states = $("#us_state").on("change", function() {
    var $cities = $.map(data[this.value], function(city) {
        return $("<option />").text(city);
    });
    $("#city_name").empty().append($cities);
});

for (var state in data) {
    $("<option />").text(state).appendTo($states);
}​

演示: http://jsfiddle.net/8hbcP/