我是flask和 的新手Javascript。我想要做的就是創建一個帶有動態下拉列表的表單，獲取選擇的值并將它們放入數據庫中?，F在我處于創建動態下拉列表的第一階段。這是代碼的我的python部分。class Form(FlaskForm): site = SelectField('Site', choices=[(' ', ' '), ('International', 'International'), ('Domestic', 'Domestic')]) location = SelectField('Location', choices=[]) city = SelectField('City', choices=[]) street = SelectField('Street', choices=[]) sub_street = SelectField('BuildingStreet', choices=[]) floor = SelectField('Floor', choices=[]) room = SelectField('Room', choices=[]) side = SelectField('Side', choices=[])@app.route('/')def basic(): return render_template('basic.html')@app.route('/Welcome', methods=['GET', 'POST'])def index(): form = Form() location_choice_list = [(locations.id, locations.location) for locations in Hostname.query.filter_by(site='International').all()] form.location.choices = remove_duplicates.unique_list(location_choice_list) city_choice_list = [(cities.id, cities.city) for cities in Hostname.query.filter_by(site='International').all()] form.city.choices = remove_duplicates.unique_list(city_choice_list) street_choice_list = [(streets.id, streets.street) for streets in Hostname.query.filter_by(site='International').all()] form.street.choices = remove_duplicates.unique_list(street_choice_list) sub_street_choice_list = [(sub_streets.id, sub_streets.sub_street) for sub_streets in Hostname.query.filter_by(site='International').all()] form.sub_street.choices = remove_duplicates.unique_list(sub_street_choice_list)所以首先我創建了一個類，其中包含用戶可以從表單中選擇的所有下拉列表。除了站點之外，所有其他選項最初都填充有對應于“國際”的選項。即“國際”對應的所有地點，“國際”對應的所有城市等等。我使用了一個小函數作為模塊來刪除數據庫中無法避免的重復條目。最初，當顯示表單時，一切都按預期進行。我沒有放置 basic.html 文件，因為它只包含一個指向“/Welcome”的鏈接。此外，我用作模塊的 remove_duplicates 函數也沒有問題。
1 回答
拉風的咖菲貓
TA貢獻1995條經驗 獲得超2個贊
您的location變量與window.location使用當前文檔 url- https://developer.mozilla.org/en-US/docs/Web/API/Window/location的變量沖突
var list = [{"id":" ","location":" "}, {"id":"CN0","location":"CN0"},{"id":"India","location":"India"},{"id":"Japan","location":"Japan"},{"id":"Honkong","location":"Honkong"},{"id":"GB0","location":"GB0"}];
const countries = document.querySelector('#countries');
let optionHTML = "";
list.forEach((obj) => {
optionHTML += '<option value="' + obj.id + '">' + obj.location + '</option>';
});
countries.innerHTML = optionHTML;
countries.addEventListener('change', function() {
location = this.value;
// alert(location);
alert(window.location === location);
});
<select name="" id="countries"></select>
而是使用不同的變量，而不是location使用block-scoped變量 usinglet或const未提升且不與全局變量沖突的變量。
var list = [{"id":" ","location":" "}, {"id":"CN0","location":"CN0"},{"id":"India","location":"India"},{"id":"Japan","location":"Japan"},{"id":"Honkong","location":"Honkong"},{"id":"GB0","location":"GB0"}];
const countries = document.querySelector('#countries');
let optionHTML = "";
list.forEach((obj) => {
optionHTML += '<option value="' + obj.id + '">' + obj.location + '</option>';
});
countries.innerHTML = optionHTML;
countries.addEventListener('change', function() {
let location = this.value;
console.log(location);
});
<select name="" id="countries"></select>
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