hw 5/23

write a javascript to let a webpage refresh itself every 60 seconds.

// ==UserScript==
// @name reload
// @namespace
// @description reload webpage after 60sec
// ==/UserScript==

(function()

{

setTimeout("document.location.reload()",60000);
})
();

HW 5/16

3.電腦硬體頻頻的升級會過度增加企業的營運成本，以Web為基礎的應用程式系統可否減低這種成本？WHY？

答:可以的.因為可以利用伺服器端來處理資料及運算,最後再傳回使用者端,這樣就可以發揮硬體的效能,近而減低成本.

4.瀏覽器支援Java,Html,JavaScript,ActiveX Control,以及各式Plug-in,這些工具分別適合用來做哪些應用？

答:java可用於動態網頁. html在於傳送與存取文字資料都很方便. javascript:用於pre-process以及post-process. active-x control對於動態網頁是一個很好的呈現方式.

5/16 Homework

Reading Assignments:Read Chapter 3.1 & 3.2
Homework
1. Problem 3.1
2. Problem 3.2
3. Do lab Tongwen
答:3.1
Secret key的優點是加密還有解密速度快,但是因為加密還有解密金鑰,資訊的傳送者如何在加密後講此祕密鑰匙交給接受者,是此密碼系統的一大問題.
3.2
大眾使用公開金鑰加密明文,僅有秘密金鑰的個人可以解開此暗文,因此第三者不能解讀暗文的內容,進而達到保密的目的.

5/2 homework

1.試解釋web技術演進是要解決什麼樣的問題?
答: 是爲了要讓網站的管理更容易,以及提高網站的scalability.

2.以網站開發的角度來說,Script語言有什麼優勢?
答:可以使學習語言更容易, 並且使網頁便些較容易.

3.程序(Process)和執行緒(Thread)對網站性能有什麼不同的影響?
答:Process比Thread更需要資源, 所以會使網站的scalability較低.

4/25 HOMEWORK

1.If Google Maps is available as web service, propose at least five applications that can make use of this service.
Ans:1) When going on a trip, we could find the fastest route to our destination without getting lost by using the mobile technology.
2) Teachers could have an alternative in teaching the geography lessons rather than showing maps on text books which may attract more attention from the students.
3)Companies could show their exact locations on the internet which gives a better impression than just giving their addresses.
4)When people are lost in the mountains or in some unkown places in the world, the rescue team could find their locations and save them before it's too late.
5)We could find the most convenient place to pay our internet fee or cell phone fee.