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
Server Application Error错误解决思路
ASP教程:在IIS环境下自己设置404页面
ASP代码出现80040e14错误的解决方法
Http_Referer,Server_Name和Http_Host
HTTP_X_FORWARDED_FOR和REMOTE_ADDR
总结的Server.Mappath的用法
巧用ASP脚本命令重启服务器
实现数字字符串的最大值、最小值和平均值
详解ASP脚本的执行顺序
理解认识阿里妈妈淘客系统对外接口通用规范
网站开发者参考:开源ASP网站源码
IIS管理程序Adsutil.vbs修改FTP服务器的PASV端口范围
ASP程序中调用函数Now()异常的问题
流量大的网站不要选择万能空间
网站挂马方式大总结
启动 W3SVC 服务报错怎么解决
Vista系统安装IIS7配置ASP运行环境
Server Application Error 8004EOOF错误
ASP不用模板直接简单生成HTML页面
ASP教程:gb2312和utf-8乱码问题解决

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: 234 ::
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.