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
使用ASP中的VB ActiveX.dll文件
用ADO的COMMAND对象实现对WEB数据库动态数据查询的方法
在ASP中使用简单Java类
借助组件使用asp连接informix全方案
用ADSI编程实现IIS中建立虚拟目录
不刷新页面筛选数据库中的数据
使用ISAPI过滤器增强IIS的功能
利用J2ME与ASP建立数据库连接
用通ASP直接获取用户真实IP地址
用ASP编写计数器的优化方法
通过ASP远程注册自己的组件
检测IP地址是否真正合法的函数
用asp做access的远程接口
错误80004005信息处理方法
ASP学习:urldecode 方法补遗
在HTML页面中实现点击数统计
ASP字数计算函数
用ASP随机生成文件名的函数
单页面判断浏览器是否接受 Cookies
存储过程介绍及asp+存储过程的使用

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: 186 ::
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.