当前位置: 首页 > 图文教程 > 网络编程 > ASP > javascript asp教程第十一课--Application 对象

ASP
ASP技巧:在Access数据库中重命名表
用ASP编程实现网络内容快速查找
比较ASP生成静态HTML文件的几种方法
ASP实例:实现邮件发送普通附件和嵌入附件
如何用ASP实现去掉三个最高分和三个最低分
ASP实例:Access为后台数据库的网站统计系统
用标签替换的方法生成静态网页
例程:用ASP判断文件地址是否有效
学ASp动态网页必备:常用的38个函数
ASP教程:初次接触学习ASP脚本程序
ASPJPEG水印中关于文字水印的帮助文档(中英文对照)
ASP例子:ASP把汉字转化为拼音的函数
ASP教程:学习ASP应用Cookies的技巧
ASP入门:认识ASP程序所使用的几种脚本语言
初学者的ASP教程:常用ASP内置函数
ASP初级教程之ASP对表单和用户输入的处理
学习ASP文件引用的方法
用ASP编写更人性化的弹出窗口程序
谈谈学习ASP动态网页制作技术的编程心得
用ASP程序实现网站在线人数统计

ASP 中的 javascript asp教程第十一课--Application 对象


出处:互联网   整理: 软晨网(RuanChen.com)   发布: 2009-09-13   浏览: 65 ::
收藏到网摘: n/a

Overview:

The Application Object represents a collection of ASP pages. The Application object has zero (0) properties, two (2) collections, two (2) methods, and two (2) events.

Get Started:

Below are a couple scripts for lesson11.

<%@LANGUAGE="JavaScript"%>
<%
//No ASP Here, just a regular HTML Page
%>
<HTML>
<FORM ACTION="script11a.asp" METHOD="Post">
<STRONG>Would you like to chose the official Application color?</STRONG><BR>
<SELECT NAME="OfficialColor">
<OPTION>red</OPTION>
<OPTION>white</OPTION>
<OPTION>blue</OPTION>
</SELECT><BR>
<INPUT TYPE="Submit" VALUE="Yes, click here">
</FORM>
No, <A HREF="script11a.asp">click here</A>.
</HTML>

Click Here to run script11.asp in a new window. Below is script11a.asp.

<%@LANGUAGE="JavaScript"%>
<HTML>
<%
Application.Lock()
var OfficialColor = new String( Request.Form("OfficialColor") )
if (OfficialColor=="red")	{	Application("OfficialColor") = "red"	}
if (OfficialColor=="white")	{	Application("OfficialColor") = "white"	}
if (OfficialColor=="blue")	{	Application("OfficialColor") = "blue"	}
if (OfficialColor=="undefined")	{	//Do nothing. Just leave the color alone.	}
Application.Unlock()
%>
<BODY BGCOLOR="<%=Application("OfficialColor")%>">
<STRONG>
The official application color is <%=Application("OfficialColor")%>.<BR>
</STRONG>
</BODY>
</HTML>

Application Collections:

The two collections are Contents and StaticObjects. StaticObjects come in the form of the <OBJECT> flag. That's done in the global.asa that we saw in Lesson 09. I'll demonstrate it again down below.

By contrast, the Contents collection is demonstrated above. It allows you to set and retrieve variables with Application scope. The format for setting an Application variable is Application.Contents("VariableName")="VariableValue". However, since Contents is the default Collection, we have a little shortcut for setting Application variables. The shortcut goes like this: Application("VariableName")="VariableValue".

Share the Variable:

One last thought on Application Variables. The application variable is shared by all visitors. Let's say that you and I are on the same ASP web site at the same time. If you set the background color to white in script11.asp, then I will see "white" as the official color if I go directly to script11a.asp. Application Variables are by no means the most efficient means of passing information from one user to another.

No Apartment Model:

You may notice that the example above seems to be inefficient. Why not just directly assign Application("OfficialColor") = Request.Form("OfficialColor")? Because we can't. By design, the newer (and updated) versions of Microsoft server software intentionally do not support Apartment Model Behavior.

Application Methods:

The two Application Methods are Lock() and Unlock(). Lock() blocks all other users from changing the Application variables. Unlock() releases control so that other users can change it. That's important on a larger site where multiple users may be trying to access the same page at the same time.

Application Events:

The two Application events are Application_OnStart() and Application_OnEnd(). These events are accessed in the global.asa. Let's repeat that script from lesson 09.

<OBJECT RUNAT=Server SCOPE=Session ID=MyInfo PROGID="MSWC.MyInfo">
</OBJECT>
<SCRIPT RUNAT="Server" LANGUAGE="JavaScript">
function Application_OnStart()	{	Application("someVariableName")="some value"	}
function Application_OnEnd()	{	Application.Contents.RemoveAll()	}
function Session_OnStart()	{	Session.Timeout=15	}
function Session_OnEnd()	{	//Do Nothing	}
</SCRIPT>
<!-- METADATA TYPE="typelib"
FILE="C:\Program Files\Common Files\System\ado\msado15.dll"
-->

Misc. Items:

Application.Contents has two methods of its own. Application.Contents.Remove("VariableName") and Application.Contents.RemoveAll().

You'll notice there are also Session Events in the global.asa. We'll deal with those in Lesson 12. You'll also notice a call to the ADO Library. We'll talk about that when we get to databases.