January 2013
Intermediate to advanced
332 pages
5h 23m
Chinese
Content preview from JAVASCRIPT網頁應用程式設計
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
208
|
第十二章
委派事件
委派事件機制，能讓設定
el
的事件處理器這項工作，變得很簡單。如果想替檢視器設
定多組事件，以及相對應的回叫函式，可以這麼寫：
var TodoView = Backbone.View.extend({
events: {
"change input[type=checkbox]" : "toggleDone",
"click .destroy" : "clear",
},
toggleDone: function(e){ /* ... */},
clear: function(e){ /* ... */}
});
用來設定 event 的雜湊物件（hash）格式是
{" 事件類型 選取項 ": " 回叫函式 "}
。「選取
項」可以不設定，如果沒有設的話，就會直接將這組事件和
el
綁在一起。如果有設定
的話，就會把事件委派（
http://api.jquery.com/delegate
）給符合選取項查詢條件的
el
子
元件。也就是說，
el
的子元件中，所有符合選取項的元件，都會和這組事件綁在一起。
委派事件機制採用的是氣泡傳播模式（event bubbling），因此就算
el
的內容有被更動，
這些事件還是會被觸發。
「回叫函式」的部分是設定一組字串，這組字串要對應到檢視器裡的某個實體函式名
稱。當檢視器的事件回叫函式被觸發時，回叫函式裡的執行環境（context）會和檢視
器的執行環境一致，而不會和觸發事件的網頁元件、或視窗的執行環境一致。這點對
我們而言很方便，因為這麼一來，就可以直接在回叫函式 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.