Use Backbone.js to create an example code for adding, deleting, modifying and looking up tables

Backbone.js is a heavyweight web development framework. It is a js framework based on jquery and underscore. It mainly consists of three parts: Model, Collection, and View.
1.Model: Create a model to represent the data object, perform data verification, destroy the object or save it to the server.
2.Collection: It is a collection of Models that can add or delete elements, as well as some convenient operations.
3.View: You can bind html templates and events, you can render models or collections onto the page, and you can re-render the page by listening to events such as model changes or destruction.
The advantage of Backbone is that it separates data and interface well, and strips out event bindings, which facilitates management and iteration, making the modularization of Javascript clearer. Backbone is more suitable for situations where there is a large amount of data on the page, making it easier to communicate complex information within the page.

Below I used Backbone to write a table for adding, deleting, modifying, and checking, referring to the Todos example on Backbone's official website. Backbone.js itself relies on jquery and underscore. For data storage, I used backbone-localstorage.js to store data in a local database. I posted the main js code. A lot of jquery, underscore and backbone methods and events are used, please refer to the relevant documents.

$(function(){

	//Model:表示一个学生
	var Student=Backbone.Model.extend({
		//默认值
		defaults:function(){
			return{
				name:"XXX",
				age:"0",
				selected:false,
				id:Students.nextId(),
			};
		},
		
		//初始化的时候判断，如果设置的属性值非法就设为默认值
		initialize:function(){
			if(!this.get("name")){
				this.set({"name":this.defaults().name});
			}
			if(!this.get("age")||!(/(^[1-9]\d*$)/.test(this.get("age")))){
				this.set({"age":this.defaults().age});
			}
		},

		//标记该学生是否被选中
		toggle:function(){
			this.save({selected:!this.get("selected")});
		}
	});

	//Collection:Model的集合，即所有学生的集合
	var Students=Backbone.Collection.extend({
		
		model:Student,
		
		//本地数据库，用到backbone-localstorage.js
		localStorage:new Backbone.LocalStorage("Students-Table"),

		//返回被选中的学生的集合
		selected:function(){
			return this.filter(function(student){return student.get('selected');});
		},

		//给每个学生一个编号
		nextId:function(){
			if(!this.length)
				return 1;
			return this.last().get('id')+1;
		}
	});

	//定义一个学生集合对象
	var Students=new Students;


	//View:这个视图表示table中的一列，即一个学生，对应一个Model
	var StudentView=Backbone.View.extend({
		//表示<tr></tr>元素
		tagName:"tr",
		
		//将相应模板写入template属性中，_.template()为underscore.js中的方法
		template:_.template($(&#39;#item-template&#39;).html()),

		//绑定该tr下的事件
		events:{
			"click .toggle":"toggleSelect",
			"dblclick td":"edit",
			"click a.destroy":"clear",
			"blur .edit":"close"
		},

		//初始化该View，listenTo监听model的事件
		initialize:function(){
			//model发生变化就重新渲染视图
			this.listenTo(this.model,&#39;change&#39;,this.render);
			//销毁model
			this.listenTo(this.model,&#39;destroy&#39;,this.remove);
		},

		//this.$el为该tr节点元素，将template渲染进该节点，并把model的值写入
		render:function(){
			this.$el.html(this.template(this.model.toJSON()));
			//如果该行被选中，则切换样式
			this.$el.toggleClass(&#39;selected&#39;,this.model.get(&#39;selected&#39;));
			return this;
		},

		//判断该行是否被选中，对应model中的selected属性
		toggleSelect:function(){
			this.model.toggle();
		},

		//双击td将样式变为可编辑
		edit:function(e){
			$(e.currentTarget).addClass("editing").find("input,select").focus();
		},

		//编辑状态下失去焦点，则修改完成
		close:function(e){
			var input=$(e.currentTarget);

			if(input.attr(&#39;name&#39;)=="name"){
				if(!input.val()){
					input.val(this.model.defaults().name);
				}
				this.model.save({"name":input.val()});
			}else if(input.attr(&#39;name&#39;)=="gender"){
				this.model.save({"gender":input.val()});
			}else{
				if(!input.val()||!(/(^[1-9]\d*$)/.test(input.val()))){
					input.val(this.model.defaults().age);
				}
				this.model.save({"age":input.val()});
			}
			input.parent().removeClass("editing");
		},

		//删除该行的时候删除相应model
		clear:function(){
			this.model.destroy();
		}
	});


	//View:这个视图表示$("#content")，用来表现整个学生表格
	var AppView=Backbone.View.extend({
		el:$("#content"),

		//右下角删除学生数目的模板
		statsTemplate:_.template($(&#39;#stats-template&#39;).html()),

		events:{
			"click #add-student":"addNewStudent",
			"click #clear-selected":"clearSelected",
			"click #select-all":"selectAll"
		},

		initialize:function(){
			this.allCheckbox=$("#select-all");
			this.main=$("#main");
			this.footer=$(&#39;footer&#39;);
			this.name=$("#new-name");
			this.age=$("#new-age");
			this.gender=$("#new-gender");

			//Collection中增加一个Model就触发add事件
			this.listenTo(Students,&#39;add&#39;,this.addOne);
			//一旦调用fetch方法就触法reset事件
			this.listenTo(Students,&#39;reset&#39;,this.addAll);
			//all事件表示该View下的所有事件，即触法任意事件就触法all事件
			this.listenTo(Students,&#39;all&#39;,this.render);

			//从本地数据库中获取所有学生
			Students.fetch();
		},

		//渲染视图
		render:function(){
			var selected=Students.selected().length;
			
			if(Students.length){
				this.main.show();
				this.footer.show();
				this.footer.html(this.statsTemplate({selected:selected}));
			}else{
				this.main.hide();
				this.footer.hide();
			}
			//判断所有学生是否被选中
			this.allCheckbox.attr("checked",selected==Students.length?true:false);
		},

		//增加一个学生，同时将model传入StudentView中
		addOne:function(student){
			var view=new StudentView({model:student});
			//将渲染后的每一列添加到表格中
			this.$("#student-list").append(view.render().el);
		},

		//增加所有学生，通过Collection.each依次调用addOne方法
		addAll:function(){
			Students.each(this.addOne,this);
		},

		//增加一个新学生
		addNewStudent:function(){
			Students.create({name:this.name.val(),gender:this.gender.val(),age:this.age.val()});
			this.name.val(&#39;&#39;);
			this.age.val(&#39;&#39;);
			this.gender.val(1);
		},

		//删除选中列，_.invoke(集合,方法)
		clearSelected:function(){
			_.invoke(Students.selected(),&#39;destroy&#39;);
		},

		//选中所有
		selectAll:function(){
			var selected=this.allCheckbox.attr(&#39;checked&#39;)=="checked";
			Students.each(function(student){
				student.save({&#39;selected&#39;:selected});
			});
		}
	});

	//创建View
	var App=new AppView;
});

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