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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第七章
處理檔案
讀寫檔案的功能，在過去往往只能在桌面應用程式裡看得到。如果想讓網頁程式也具備
相關功能，就得要透過諸如 Adobe Flash 之類的外掛模組。直到 HTML5 的問世，才改
變了這一切。HTML5 讓網頁程式設計師能對檔案進行更多樣化的處理，也讓網頁應用
程式變得更像桌面應用程式。如今，使用者只要擁有最新的瀏覽器，就能在網頁上拖
曳 / 置放檔案、複製 / 貼上結構化資料，也能在上傳檔案的同時，即時看到檔案上傳的
進度。
支援的瀏覽器
雖然並非所有瀏覽器都支援 HTML5 所提供的新版檔案 API，但已有相當數量的瀏覽器
提供相關的實作，多花些心力將它整進自己的應用程式中，絕對是值得的。
• Firefox >= 3.6
• Safari >= 6.0
• Chrome >= 7.0
• IE：不支援
• Opera >= 11.1
由於 IE 不支援此 API，因此必須採用「漸進增強（progressive enhancement）」的做法：
除了提供最新的拖曳 / 置放檔案功能之外，還要主動偵測使用者的瀏覽器是否支援此
API，如果發現不支援，就讓使用者改用舊式的選檔功能。偵測瀏覽器是否有支援 API
的做法相當簡單—只要檢查 API 的幾個主要物件是否存在即可：
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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.