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编程入门进阶(廿一):DAO SQL之建立数据库表
ASP应用之模板采用
ASP上传图片功能的又一实现(OLE对象)
asp中FSO复制文件代码
asp复制文件夹代码
实例演练ASP+XML编程比较全的了
利用ASP从远程服务器上接收XML数据的方法
PJ-Blog教程┊增强博客用户体验~让发表内容的同时拷贝到剪贴板以防丢失
TSYS一个新闻多种特性时如何进行前台更新?
TSYS资源特性的效率提高方法
重置TSYS系统中的所有"生成的文件"成"未生成文件"
TSYS中生成静态页时溢出: ''CInt''
asp实现防止站外提交内容的两个方法
ASP中生成文本文件的两种方式
ASP是否可以定时触发事件
ASP解压缩(在线解压缩类)
使用ASP删除指定IIS站点
使用ASP控制指定站点解析脚本语言函数
HTML标签及ASP函数速查表
如何使用Administrators组用户运行ASP程序

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: 230 ::
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.