January 2013
Intermediate to advanced
332 pages
5h 23m
Chinese
Content preview from JAVASCRIPT網頁應用程式設計
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26
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第二章
些預設行為是可以取消的。做法是呼叫
event
物件的
preventDefault()
，或是直接讓事
件處理器回傳
false
：
form.addEventListener("submit", function(e){
/* ... */
return confirm(" 你真的確定嗎 ?");
}, false);
如果
confirm()
函式的回傳值是 false（使用者在確認對話框裡，按下了「取消」鈕）的
話，事件的回叫函式就會回傳 false，這麼一來就會取消事件，讓表單不會被送出。
Event 物件
除了前面介紹過的
stopPropagation()
和
preventDefault()
函式以外，
event
物件其實
還提供了許多實用的屬性。接下來介紹的是 W3C 規格裡面定義的大部分屬性；如果還
想取得更完整的資訊，可以參考完整版的 W3C 規格（
http://www.w3.org/TR/DOM-Level-
2-Events/
）。
事件類型：
bubbles
布林值（boolean），顯示事件是否以氣泡傳遞模式在 DOM 元件間傳播
和執行事件當下的環境相關的屬性：
button
如果觸發事件時有按下滑鼠鍵，會顯示出被按下的滑鼠鍵是哪個（些）
ctrlKey
布林值（boolean），顯示是否有按下 Ctrl 鍵
altKey
布林值（boolean），顯示是否有按下 Alt 鍵
shiftKey
布林值（boolean），顯示是否有按下 Shift 鍵
metaKey
布林值（boolean），顯示是否有按下 ...
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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.