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Javascript的痛點就是物件導向編程，上一篇介紹了Javascript的兩種繼承方式：Javascript 進階 繼承，這篇使用一個例子來展示js如何物件導向編程，以及如何基於類實現繼承。
1、利用物件導向的寫法，實現下面這個功能，即時更新資料的一個例子：
2、使用對上面類的繼承，完成下面的效果：
好了，不多說，js的訓練全靠敲，所以如果覺得物件導向不是很紮實，可以照著敲一個，如果覺得很紮實了，提供了效果圖，可以自己寫試試。
1、第一個效果圖代碼：
/** * Created with JetBrains WebStorm. * User: zhy * Date: 14-6-7 * Time: 下午4:55 * To change this template use File | Settings | File Templates. *//** * @param id * @param value * @param parentEle 父元素 * @constructor */function PlaceFieldEditor(id, value, parentEle){ this.id = id; this.value = value; this.parentEle = parentEle; this.initValue = value ; this.initElements(); this.initEvents();}PlaceFieldEditor.prototype = { constructor: PlaceFieldEditor, /** * 初始化所有元素 */ initElements: function () { this.txtEle = $("<span/>"); this.txtEle.text(this.value); this.textEle = $("<input type='text' />"); this.textEle.val(this.value); this.btnWapper = $("<div style='display: inline;'/>"); this.saveBtn = $("<input type='button' value='儲存'/>"); this.cancelBtn = $("<input type='button' value='取消'/>"); this.btnWapper.append(this.saveBtn).append(this.cancelBtn); this.parentEle.append(this.txtEle).append(this.textEle).append(this.btnWapper); this.convertToReadable(); }, /** * 初始化所有事件 */ initEvents: function () { var that = this; this.txtEle.on("click", function (event) { that.convertToEditable(); }); this.cancelBtn.on("click", function (event) { that.cancel(); }); this.saveBtn.on("click", function (event) { that.save(); }); }, /** * 切換到編輯模式 */ convertToEditable: function () { this.txtEle.hide(); this.textEle.show(); this.textEle.focus(); if(this.getValue() == this.initValue ) { this.textEle.val(""); } this.btnWapper.show(); }, /** * 點擊儲存 */ save: function () { this.setValue(this.textEle.val()); this.txtEle.html(this.getValue().replace(/\n/g,"<br/>")); var url = "id=" + this.id + "&value=" + this.value;// alert(url); console.log(url); this.convertToReadable(); }, /** * 點擊取消 */ cancel: function () { this.textEle.val(this.getValue()); this.convertToReadable(); }, /** * 切換到查看模式 */ convertToReadable: function () { this.txtEle.show(); this.textEle.hide(); this.btnWapper.hide(); }, setValue: function (value) { this.value = value; }, getValue: function () { return this.value; }};
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head> <title></title> <script type="text/javascript" src="jquery-1.8.3.js"></script> <script type="text/javascript" src="PlaceFieldEditor.js"></script> <script type="text/javascript"> $(function () { $("ul li").each(function () { new PlaceFieldEditor($(this).attr("id"), "請輸出成績...", $(this)); }); }); </script> <style type="text/css"> body { font-size: 12px; color: #333;; } ul li { line-height: 30px; } </style></head><body><ul> <li id="1">張三：</li> <li id="2">李四：</li> <li id="3">王二：</li></ul></body></html>嗯，代碼就不詳細說了，都比較簡單，使用了jQuery，如果不喜歡可以使用原生js，本人比較喜歡把jQuery當作js的工具使用。
2、第二個效果圖的js代碼：
/** * Created with JetBrains WebStorm. * User: zhy * Date: 14-6-7 * Time: 下午5:34 * To change this template use File | Settings | File Templates. */function PlaceAreaEditor(id, value, parentEle){ PlaceAreaEditor.superClass.constructor.call(this, id, value, parentEle);}extend(PlaceAreaEditor, PlaceFieldEditor);PlaceAreaEditor.prototype.initElements = function (){ this.txtEle = $("<span/>"); this.txtEle.text(this.value); this.textEle = $("<textarea style='width:315px;height:70px;' />"); this.textEle.text(this.value); this.btnWapper = $("<div style='display: block;'/>"); this.saveBtn = $("<input type='button' value='儲存'/>"); this.cancelBtn = $("<input type='button' value='取消'/>"); this.btnWapper.append(this.saveBtn).append(this.cancelBtn); this.parentEle.append(this.txtEle).append(this.textEle).append(this.btnWapper); this.convertToReadable();};
extend的方法，上一篇部落格已經介紹過：
/** * @param subClass 子類 * @param superClass 父類 */function extend(subClass, superClass){ var F = function () { }; F.prototype = superClass.prototype; //子類的prototype指向F的_proto_ ， _proto_又指向父類的prototype subClass.prototype = new F(); //在子類上儲存一個指向父類的prototype的屬性，便於子類的構造方法中與父類的名稱解耦 使用subClass.superClass.constructor.call代替superClass.call subClass.superClass = superClass.prototype;}最後頁面代碼：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head> <title></title> <script type="text/javascript" src="jquery-1.8.3.js"></script> <script type="text/javascript" src="PlaceFieldEditor.js"></script> <script type="text/javascript" src="com.zhy.extend.utils.js"></script> <script type="text/javascript" src="PlaceAreaEditor.js"></script> <script type="text/javascript"> $(function () { $("ul li div").each(function () { new PlaceAreaEditor($(this).attr("id"), "請留言...", $(this)); }); }); </script> <style type="text/css"> body { font-size: 12px; color: #333;; } ul li { padding: 5px 0 8px 0 ; } </style></head><body><ul> <li id="1"><h3>我要改劇本，不讓~~</h3> <div> </div> </li> <li id="2"><h3>懸崖上有橋麼，有。沒有~ </h3> <div> </div> </li> <li id="3"><h3>你敢打壞我的燈。不租~ </h3> <div> </div> </li></ul></body></html>
代碼或者講解有任何問題，歡迎留言指出。
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