问题 单项选择题

Ajax是目前基于Web 2.0的Web应用系统广泛使用的表现层技术之一。在使用Ajax时,从效率方面考虑需要注意的问题不包括______。

A.不要在没有必要的情况下使用轮询计时器
B.利用客户端的动态特性和计算能力以减轻服务端负载
C.针对不同的应用情况,尽量考虑传递相同格式的数据
D.替换部分而不是全部HTML网页

答案

参考答案:C

解析: Web 2.0是目前Internet上Web应用的新模式。事实上,Ajax并不是一种全新的技术,而是几种现有技术的组合:①XHTML和CSS②使用文档对象模型(Document Object Model)做动态显示和交互;③使用XML和XSLT做数据交互和操作;④使用XML Http Request进行异步数据接收;⑤使用JavaScript将它们绑定在一起。
针对这些技术的特点,在使用Ajax时,从性能方面考虑,需要注意以下几个问题。
①替换部分而不是全部HTML网页(这是Ajax核心思想的体现)。
②不要在没有必要的情况下使用轮询计时器(由于JavaScript是单线程的语言,不恰当的使用轮询计时器会大大降低程序的运行效率)。
③根据不同的情况,考虑传递不同格式的数据(JavaScript、XML、HTML和XHTML等)。
④充分利用客户端的动态特性和计算能力减轻服务端负载。

阅读理解

阅读理解。

     His songs are a bit sad, but his boy-like smile can quickly warm you up! And people love A-do for both

reasons.

     He has been singing for only two years, but he's already a famous star in Asia's pop world. The Singaporean

singer has already made three albums. Together they have sold more than five million copies across Asia.

     China's Music Radio named him "the Asian King of Pop". A-do said he didn't expect the award (奖)."It's

great for me. It makes me want to work even harder."

     His new album "Hello" came out in December. He sings with the same rough (粗糙的) voice, and he puts

in some rock music. In the "Hello" music video, Vicky Zhao (赵薇) is with A-do outside on a cold day in

Northern China.

     A-do used to be a house builder. Every day after work, he would sing by himself. Other workers heard

him and told him he should be in a contest.

     A-do hasn't changed much. He still gets nervous in front of cameras. Peng Yiting, a junior at a middle

school, says, "He's real and doesn't show off (炫耀). He's an everyday hero and shows anyone can do well

if they work hard."

1-2. 判断正(T)误(F)。 3. 译为汉语。 4 .补单词。 5. 选择。

(     )1. A-do's albums can warm you up.

(     )2. A-do has been singing for only two years.

3. China's Music Radio named him "the Asian King of Pop".

    ________________________________________________________________

4. Other workers heard him _____ and told him he should be in a contest.

5. What was A-do before he became a famous singer?

A. A builder.

B. A businessman.

C. A teacher.

填空题