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中实现限制IP的函数详解
Asp下实现限制IP访问的程序代码
asp下DateDiff 函数参数说明
Highlight patterns within strings
Insert Date and Time into Access
asp下调试程序的debug类
RESPONSE.WRITE和<%=%的区别
用asp实现网页邮箱访问的方法
编写一个含二级目录的源码(Asp+JavaScript)
asp下删除Access数词库中的空记录的sql语句
asp下制做行背景颜色交替变换的表格
asp下将数据库中的信息存储至XML文件中
asp下如何在Access数据库中立即得到所插入记录的自动编号?
asp下如何在ADO服务器端利用好缓存技术?
asp调用Word打印的代码
巧用FileSystem组件实现WEB应用中的本地特定打印的方法
用javascript解决外部数据抓取中的乱码问题
Asp中随机产生用户密码的代码
反SPAM新思路—换Z-BLOG的验证码!
在Z-BLOG可用的新版ASP的GIF验证码[V70404]

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: 68 ::
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.