网站中运用Flash技术的优点和缺点_Flash教程

推荐：新手来看：Flahs as入门教程
这里我只简单的介绍一下AS的基本常识。首先我们要了解AS要写在什么地方，什么时候AS会被触发执行。1、帧：写在要害帧上面的AS，当时间轴上的指针走到这个要

Flash is a powerful web technology that achieves a high level of visual impact from the graphical point of view. Unfortunately, it is widely misused in web design. There are still many problems with Flash, especially related to usability and search engine behaviour; we need to thoroughly understand what those problems are before we decide to use Flash for our site.

Flash是一种功能强大的网站设计技术，从绘图学观点来说，Flash确实能产生高水平的视觉影响力。然而，很多网站乱用Flash技术，致使网站出现某些运行问题。在可用性以及与搜索引擎的关系方面，Flash仍然存在自身的缺点，所以在运用Flash以前，我们需要首先了解它可能引发的几个问题。

As with any business decision, it all boils down to understanding what our target audience wants.

在做任何业务决策之前，都必须考虑目标客户的需要。

If you want to make a big impression from a graphical point of view, Flash is definitely a good approach. However, concrete evidence still points to the fact that most web users utilize the web to find information, and what they regard most important is:

从绘图学观点来说，假如希望网站给客户留下深刻的印象，使用Flash就是一种好方法。然而，很多实事证实：大部分用户只是利用网站搜索信息，它们认为网站最重要的是：

a) quality of content

内容质量

b) ease of navigation, and

简便的导航系统，以及

c) speed.

下载速度

Users also consider the web a highly interactive medium: they are unlikely to watch a computer screen for long periods of time without giving some sort of input.

同时，用户认为网络是一种互动媒体：他们不会长时间浏览电脑屏幕，肯定要输入相关内容。

Flash technology presents several problems that go against the way most people use the web. For example:

Flash技术会引发几个问题，在网站运行中，会给大多数用户带来麻烦。

 Bandwidth and Load Time Constrains: Sites designed with Flash take a long time to download and consume vast amounts of bandwidth. Not all users have a broadband connection. Flash forces users with dial-up connections to spend valuable time watching the load bar, instead of getting to the information they want, fast.

带宽与下载时间的限制：用Flash技术设计的网站，占用大量的宽带空间，下载速度很慢。一定记住：并不是所有用户都利用宽带上网。在登录Flash网站时，电话拨号上网的用户必须花费宝贵时间观看下载条，而不能快速获取需要的信息。

 Usability Constrains: When you navigate a Flash site designed with a older version, the back button does not work: instead of taking you to the previous screen, it will get you out of the Flash site. Also, the standard colors for visited and unvisited links will not work, and users have no control over the text size they want to use.

可用性限制：用老版本Flash设计的网站，后退键没有作用：点击后退键会使你退出Flash网站，而不是返回上一层网页。同时，链接以及非链接的标准颜色会发生改变，并且用户须控制需要利用的文本尺寸。

 Furthermore, many times Flash sites go against the interactive nature of the web. Since Flash technology favors a "presentation style" approach that resembles television, users are many times reduced to mere observers that get bored after a while, no matter how good the graphics look.

而且，Flash 经常带来网站交互问题。由于Flash支持类似于电视的呈现模式方法，所以用户经常作为观赏者出现。不管画面多么精美，过一段时间，用户就会对内容产生厌烦。

 Search Engine Constrains: Although large search engines like Google now have some Flash indexing capabilities, these are still very limited. You will definetely have a hard time achieving high rankings with a Flash site. One option around this problem is to design a second, search-engine-friendly HTML version of your site. This, though, usually represents an unnecessary expense in both time and money, since in most cases the HTML version alone will get the job done.

搜索引擎的限制：尽管像Google这样的大型搜索引擎，现在具备了对Flash做索引的能力，但搜索内容仍然非常有限，所以Flash网站不会在搜索引擎中获得好的排名。解决这个问题的一种方法是：利用HTML设计网站，这样的网站会有一个好的排名。利用Flash设计网站，会增加不必要的金钱和时间开支，其实 HTML网页就可以完成所有的功能。

Although few, there are some instances when Flash technology can actually be helpful:

尽管Flash存在以上几个缺点，但它同样有自己的优点：

a) When you need to show a presentation, for example a demo of your product.

可以运用Flash，展示内容，比如：展示公司样品。

b) To develop interactive games, like those found on sites for kids like Sesame Street, Nickelodeum, or Yahoo! Games.

开发互动游戏时，可以运用Flash，比如：Sesame Street、 Nickelodeum, 、Yahoo! Games等儿童游戏，都使用了Flash

c) When you want to dress up a minimalist site. In this case, a small Flash animation or banner embedded in an HTML document will not consume excessive bandwidth, will load fast, and will enhance the appearance of a bare-bones site.

当你想装饰简约网站时，你可以运用小型Flash动画，或者在HTML文件中插入标语性质的Flash，这样不会占用过多的宽带空间，下载速度很快，并且可以增加网站的观赏性。

Although Macromedia (the company that developed Flash) is actively working to improve Flash's usability problems (they even formed a partnership with usability guru Jakob Nielsen in 2002), issues like slow downloads and search engine un-friendliness still remain a problem. Until these issues are addressed and solved, you will be better-off by only using Flash in those rare instances when it actually enhances the value of your content.

尽管，Macromedia（Flash开发公司）正在积极采取方法改善Flash的可用性问题（甚至在2002年组成以网站可用性研究专家Jakob Nielsen为首的工作组，专门研究这个问题），但是下载速度慢、搜索引擎对其不友好的问题，仍然没有解决。在这些问题解决以后，假如利用Flash可以增加网站价值（少数情况），那你可以运用。

分享：Flash简单制作光晕动画效果
下面我们来做一个模拟光斑的效果，效果如上图，这一课主要学习色彩的调节变换，因为调节出好的色彩才会使图像更加亮丽，增加层次感和视觉效果。调出好的色彩谁