jQuery 學習筆記(jQuery: The Return Flight)

第一課.

ajax：$.ajax(url[, settings])

練習代碼：

$(document).ready(function() {$("#tour").on("click", "button", function() {$.ajax('/photos.html', {success: function(response) {$('.photos').html(response).fadeIn();}});});
});

<div id="tour" data-location="london"><button>Get Photos</button><ul class="photos"></ul>
</div>

ajax 調用簡寫：$.get(url, success)

$(document).ready(function() {$("#tour").on("click", "button", function() {$.get('/photos.html', function(response) {$('.photos').html(response).fadeIn();});});
});

ajax?傳遞參數：直接在 url 中拼接或使用 data 對象傳遞，data: { "confNum": 1234 }

練習代碼：獲取網頁元素中的?data 屬性值作為 ajax 參數值傳遞

$(document).ready(function() {$("#tour").on("click", "button", function() {$.ajax('/photos.html', {success: function(response) {$('.photos').html(response).fadeIn();},data: { "location": $("#tour").data("location")}});});
});

<div id="tour" data-location="london"><button>Get Photos</button><ul class="photos"></ul>
</div>

第二課.

ajax?異常處理：error: function(request, errorType, errorMessage) { }

ajax?超時設定：timeout: 3000

ajax?調用前（beforeSend: function() {}）完成后（complete: function() {}）執行方法：

練習代碼：

$(document).ready(function() {var el = $("#tour");el.on("click", "button", function() {$.ajax('/photos.html', {data: {location: el.data('location')},success: function(response) {$('.photos').html(response).fadeIn();},error: function(request, errorType, errorMessage) {//var errmsg = $("<li>Error: " + errorType + " with message: " + errorMessage + "</li>");//$('.photos').append(errmsg);//alert('Error: ' + errorType + ' with message: ' + errorMessage);$('.photos').html('<li>There was a problem fetching the latest photos. Please try again.</li>');},timeout: 3000,beforeSend: function() {$("#tour").addClass("is-fetching")},complete: function() {$("#tour").removeClass("is-fetching")}});});
});

<div id="tour" data-location="london"><button>Get Photos</button><ul class="photos"></ul>
</div>

ajax 事件處理：處理 ajax 完成新增的標簽元素的事件

練習代碼：

$(document).ready(function() {function showPhotos() {$(this).find('span').slideToggle();}$('.photos').on('mouseenter', 'li', showPhotos).on('mouseleave', 'li', showPhotos);var el = $("#tour");el.on("click", "button", function() {$.ajax('/photos.html', {data: {location: el.data('location')},success: function(response) {$('.photos').html(response).fadeIn();},error: function() {$('.photos').html('<li>There was a problem fetching the latest photos. Please try again.</li>');},timeout: 3000,beforeSend: function() {$('#tour').addClass('is-fetching');},complete: function() {$('#tour').removeClass('is-fetching');}});});
});

HTML、AJAX Result

<div id="tour" data-location="london"><button>Get Photos</button><ul class="photos"></ul>
</div>

<li><img src="/assets/photos/paris1.jpg"><span style="display: none;">Arc de Triomphe</span>
</li>
<li><img src="/assets/photos/paris2.jpg"><span style="display: none;">The Eiffel Tower</span>
</li>
<li><img src="/assets/photos/london.jpg"><span style="display: none;">London</span>
</li>

第三課.?

JavaScript Objects：

練習代碼：

重構前：

$(document).ready(function() {$("#tour").on("click", "button", function() {$.ajax('/photos.html', {data: {location: $("#tour").data('location')},success: function(response) {$('.photos').html(response).fadeIn();},error: function() {$('.photos').html('<li>There was a problem fetching the latest photos. Please try again.</li>');},timeout: 3000,beforeSend: function() {$('#tour').addClass('is-fetching');},complete: function() {$('#tour').removeClass('is-fetching');}});});
});

重構為 JavaScript 對象 tour 后：

var tour = {init: function() {$("#tour").on("click", "button", this.fetchPhotos);},fetchPhotos: function() {$.ajax('/photos.html', {data: {location: $("#tour").data('location')},success: function(response) {$('.photos').html(response).fadeIn();},error: function() {$('.photos').html('<li>There was a problem fetching the latest photos. Please try again.</li>');},timeout: 3000,beforeSend: function() {$('#tour').addClass('is-fetching');},complete: function() {$('#tour').removeClass('is-fetching');}})}
}
$(document).ready(function() { tour.init();
});

第四課.

JavaScript Functions：重點理解 this 變量的作用域

ajax 回調函數中應用調用函數變量?this 時，需要首先在 ajax 的 context 參數中傳入調用函數的 this 變量：

練習代碼：

function Tour(el) {var tour = this;this.el = el;this.photos = this.el.find('.photos');this.fetchPhotos = function() { $.ajax('/photos.html', {data: {location: tour.el.data('location')},context: tour,success: function(response) {this.photos.html(response).fadeIn();},error: function() {this.photos.html('<li>There was a problem fetching the latest photos. Please try again.</li>');},timeout: 3000,beforeSend: function() {this.el.addClass('is-fetching');},complete: function() {this.el.removeClass('is-fetching');}});}this.el.on('click', 'button', this.fetchPhotos);
}$(document).ready(function() { var paris = new Tour($('#paris'));var london = new Tour($('#london'));
});

<div id="paris" data-location="paris"><button>Get Paris Photos</button><ul class="photos"></ul>
</div><div id="london" data-location="london"><button>Get London Photos</button><ul class="photos"></ul>
</div>

第五課.

Ajax Forms

$('form').on('submit', function(event) {}); ?//表單提交事件

event.preventDefault(); //阻止瀏覽器的默認表單提交行為

type: 'POST' // POST 方式提交

data:{ "destination": $('#destination').val(),?"quantity": $('#quantity').val() } //獲取表單中的元素值提交數據

data: $('form').serialize() //通過表單序列化，提交整張表單中的數據

練習代碼：

$(document).ready(function() {$('form').on('submit', function(event) {event.preventDefault();$.ajax('/book', {type: 'POST',data: $('form').serialize(),success: function(response){$('.tour').html(response);}});});
});

<div class="tour" data-daily-price="357"><h2>Paris, France Tour</h2><p>$<span id="total">2,499</span> for <span id="nights-count">7</span> Nights</p><form action="/book" method="POST"><p><label for="nights">Number of Nights</label></p><p><input type="number" name="nights" id="nights" value="7"></p><input type="submit" value="book"></form>
</div>

第六課.

Ajax with JSON

dataType: 'json' // 通知服務器提交的數據類型為 json

contentType: 'application/json' //要求服務器返回的數據類型為 json

attr(<attribute>) //獲取 html 對象的屬性

attr(<attribute>, <value>) //給 html 對象的屬性賦值

練習代碼：

$(document).ready(function() {$('form').on('submit', function(event) {event.preventDefault();$.ajax($('form').attr('action'), {type: $('form').attr('method'),data: $('form').serialize(),dataType: 'json',success: function(response) {$('.tour').html('<p></p>').find('p').append('Trip to ' + response.description).append(' at $' + response.price).append(' for ' + response.nights + ' nights').append('. Confirmation: ' + response.confirmation);}});});
});

<div class="tour" data-daily-price="357"><h2>Paris, France Tour</h2><p>$<span id="total">2,499</span> for <span id="nights-count">7</span> Nights</p><form action="/book" method="POST"><p><label for="nights">Number of Nights</label></p><p><input type="number" name="nights" id="nights" value="7"></p><input type="submit" value="book"></form>
</div>

第七課.

Utility Methods

$.each(collection, function(<index>, <object>) {}) //iterate through the array

練習代碼：

$('button').on('click', function() {$.ajax('/cities/deals', {contentType: 'application/json',dataType: 'json',success: function(result) {$.each(result, function(index, dealItem) {var dealElement = $('.deal-' + index);dealElement.find('.name').html(dealItem.name);dealElement.find('.price').html(dealItem.price);});}});
});

$.getJSON(url, success); //result will be an array of?avaScript Objects

練習代碼：

$('button').on('click', function() {$.getJSON('/cities/deals', function(result) {$.each(result, function(index, dealItem) {var dealElement = $('.deal-' + index);dealElement.find('.name').html(dealItem.name);dealElement.find('.price').html(dealItem.price);});});
});

$.map(collection, function(<item>, <index>){});

練習代碼：

$('.update-available-flights').on('click', function() {$.getJSON('/flights/late', function(result) {var flightElements = $.map(result, function(flightItem, index){var liItem = $('<li></li>');liItem.append('<p>'+flightItem.flightNumber+'</p>');liItem.append('<p>'+flightItem.time+'</p>');return liItem;});$('.flight-times').html(flightElements);});
});

$.each vs $.map

.detach() //.detach() removes an element from the DOM, preserving all data and events.?

detach() 方法移除被選元素，包括所有文本和子節點。

這個方法會保留 jQuery 對象中的匹配的元素，因而可以在將來再使用這些匹配的元素。

detach() 會保留所有綁定的事件、附加的數據，這一點與 remove() 不同。

練習代碼：

$('.update-available-flights').on('click', function() {$.getJSON('/flights/late', function(result) {var flightElements = $.map(result, function(flightItem, index){var flightEl = $('<li>'+flightItem.flightNumber+'-'+flightItem.time+'</li>');return flightEl;});$('.flight-times').detach().html(flightElements).appendTo('.flights');});
});

第八課.

Managing Events：同一個元素同一個事件掛接多個事件處理程序，按順序執行