我在 Javascript 中编写了相同的代码,当用户更改状态时,它将更改城市下拉列表中的选项。
代码的问题是它不起作用。我认为该代码还可以,但是我对 JavaScript 很陌生,所以我看不到错误。
你能检查我的代码,看看我在哪里出错了。谢谢。
JavaScript:
function drzava_promjena() {
var obj_state = document.getElementById("id_drzava")
var index = obj_states.selectedIndex;
var value_state = obj_state.options[index].value;
towns = town_list[value_state];
var obj_town = document.getElementById("id_gradovi");
while (obj_town.options.length > 0) {
obj_town.remove(0);
}
var new_value;
for (var i = 0; i < towns.length; i++) {
new_value = document.createElement("option");
new_value.value = towns[i];
new_value.text = towns[i];
try {
obj_town.add(new_value);
} catch (e) {
obj_town.appendChild(new_value);
}
}
这是 HTML:
<select id="id_drzava" onchange="drzava_promjena(this);">
<option value="Austrija">Austrija</option>
<option value="Njemacka">Njemacka</option>
<option value="Slovenija">Slovenija</option>
<option value="Ceska">Ceska</option>
</select>
<br>
<select id="id_gradovi" onchange="">
<option value="0"></option>
</select>
<br>
<select id="id_uni" onchange="">
<option></option>
</select>