当前位置: 首页 > 图文教程 > 网络编程 > ASP > javascript asp教程第九课--cookies

ASP
Access 2000 数据库 80 万记录通用快速分页类
Microsoft JET Database Engine 错误 ''80004005'' 未指定的错误的完美解决方法
收藏的ASP常用的函数集
asp分页的一个类
ASP开发网页牢记注意事项
ASP下操作Excel技术总结分析
ASP数据岛操作类
ASP经典分页类
asp论坛在线人数统计研究
ASP调用SQL SERVER存储程序
asp输出bmp
ASP连接数据库的全能代码
ASP面向对象编程探讨及比较
web文件管理器的后续开发
一小偷类!!有兴趣的可以看看
利用ASP实现事务处理的方法
大数量查询分页显示 微软的解决办法
如何把ASP编写成DLL
asp实现树型结构
超级ASP大分页_我的类容我做主

No. « 56 57 58 59 »

技术文章搜索

关键字

ASP 中的 javascript asp教程第九课--cookies

出处:互联网   整理: 软晨网（RuanChen.com）   发布: 2009-09-13   浏览: 41 ::
收藏到网摘: n/a

Response Cookies in General:

We'll start with the Response Cookies collection. I don't think it could be any easier. You simply put the name of the cookie in the argument. The corresponding value is a string. The only time it gets complicated is when you use keys (which I demonstrate below). 

<%@LANGUAGE="JavaScript"%>
<%
var Tomorrow=new Date()
Tomorrow.setDate(Tomorrow.getDate() + 1)
myExpire = (Tomorrow.getMonth() + 1) + "/" + Tomorrow.getDate()
myExpire += "/" + Tomorrow.getFullYear()
Response.Cookies("firstCookie") = "I like cookies."
Response.Cookies("firstCookie").Expires=myExpire
Response.Cookies("secondCookie") = "ASP Cookies Are Easy."
Response.Cookies("secondCookie").Expires=myExpire
Response.Cookies("thirdCookie")("firstKey")="Here's the first Key."
Response.Cookies("thirdCookie")("secondKey")="Here's the second Key."
Response.Cookies("thirdCookie").Expires=myExpire
%>
<HTML>
We're just setting <%=Response.Cookies.Count%> cookies.<BR>
<A HREF="script09a.asp">Click Here</A> to retrieve these cookies.
</HTML>

Click Here to run the script in a new window.

Setting a cookie with ASP is pretty simple. The format is Response.Cookies("name")="value". That "value" can be either a JavaScript string or an ASP native type such as Request.Form("userEmail").

Response Cookie Keys:

If on the first page of your ASP application Response.Cookies("myOnlyCookie") is set, and subsequently on page two of your application Response.Cookies("myOnlyCookie") is reassigned a second value, then only the second value will remain. The first value is lost in this circumstance.

The solution is to either use multiple cookies or to use multiple Keys in the SAME cookie. 

Response.Cookies("thirdCookie")("firstKey")="Here's the first Key."
Response.Cookies("thirdCookie")("secondKey")="Here's the second Key."

The Setting of one or more Keys is pretty simple. It follows this format: Response.Cookies("name")("key")="value". Again, the "value" can either be a JavaScript string or ASP native type. The advantage of using keys is that you can store multiple Key/Value pairs inside the very same cookie.

Request Cookies:

Generally you will find ASP cookie management to be far easier than Client Side JavaScript cookies. Down below is the script that retrieves the cookies. 

<%@LANGUAGE="JavaScript"%>
<%
if (Response.Cookies.Count <= 0)	{	Response.Redirect("script09.asp")	}
var firstCookie = Request.Cookies("firstCookie");
var secondCookie = Request.Cookies("secondCookie");
var thirdCookie2Keys = Request.Cookies("thirdCookie")("firstKey")
thirdCookie2Keys += " " + Request.Cookies("thirdCookie")("secondKey");
%>
<HTML>
There are <%=Request.Cookies.Count%> Cookies.<BR>
1) <%=firstCookie%><BR>
2) <%=secondCookie%><BR>
3) <%=thirdCookie2Keys%><BR>
<A HREF="script09b.asp">Click Here</A> to see how we would sort cookies
if we didn't know their names.
</HTML>

Click Here to run the script in a new window.

Do I even need to explain "firstCookie" and "secondCookie"? It's so easy. However, I will have to have explain the retrieval of Keys in "thirdCookie".

We retrieve cookies in almost exactly the same way that we set them, and that goes for Keys as well. If you keep track of your Key names, then retrieving their values is pretty easy. 

var thirdCookieFirstKey = Request.Cookies("thirdCookie")("firstKey")

Deleting Cookies:

To delete a cookie, give it an expiration date in the past. The following is not in our examples, but it would work. 

var Yesterday=new Date()
Yesterday.setDate(Yesterday.getDate() - 1)
myExpire = (Yesterday.getMonth() + 1) + "/" + Yesterday.getDate()
myExpire += "/" + Yesterday.getFullYear()
Response.Cookies("firstCookie").Expires=myExpire

Cookie Crumbs:

What if you lose track of your cookie names? What if you lose your Keys? First of all, don't do that. But secondly, we have options.

We can use a VBScript Function with a for/each loop. We can use Javascript's new Enumerator( ) or we can use a pair of for Loops. We, however, cannot use JavaScript's for/in loop. This means we have to be creative. 

<%@LANGUAGE="JavaScript"%>
<%
if (Response.Cookies.Count <= 0)	{	Response.Redirect("script09.asp")	}
%>
<HTML>
<SCRIPT LANGUAGE="VBScript" RUNAT="Server">
Function forEachCookie()
dim x,y,z
for each x in Request.Cookies	if Request.Cookies(x).HasKeys then	for each y in Request.Cookies(x)	z = z & x & ":" & y & "=" & Request.Cookies(x)(y) & "; "	next	else	z = z & x & "=" & Request.Cookies(x) & "; "	end if
next
forEachCookie = z
End Function
</SCRIPT>
<%
Response.Write("<STRONG>Let's use a VBScript function to ")
Response.Write("sort out the Cookies and Keys.</STRONG><BR>\r")
var longCookie = forEachCookie()
if (longCookie)	{	longCookie = longCookie.split("; ")	for (i=0;i<=longCookie.length-1;i++)	{	Response.Write(longCookie[ i ] + "<BR>\r")	}	}
Response.Write("<HR>\r")
Response.Write("<STRONG>Let's use <I>new Enumerator( )</I> to ")
Response.Write("sort out the Cookies and Keys.</STRONG><BR>\r")
var myEnum = new Enumerator(Request.Cookies);
for (myEnum; !myEnum.atEnd() ; myEnum.moveNext() )	{	Response.Write(myEnum.item() + "=")	n=Request.Cookies(myEnum.item()).Count	if (n)	{	for (o=1;o<=n;o++)	{	Response.Write(Request.Cookies(myEnum.item())(o) + " ")	}	//Begin alternate method of using Enumerator()	Response.Write("<BR>\r<STRONG>OR... </STRONG>")	Response.Write(myEnum.item() + "=")	Response.Write(unescape(Request.Cookies(myEnum.item())))	//End alternate method	}	else	{	Response.Write(Request.Cookies(myEnum.item()))	}	Response.Write("<BR>\r")	}
Response.Write("<HR>\r")
Response.Write("<STRONG>Let's use a pair of JavaScript loops to ")
Response.Write("sort out the Cookies and Keys.</STRONG><BR>\r")
a=Request.Cookies.Count
for (b=1;b<=a;b++)	{	d = Request.Cookies(b).Count	if (d)	{	for (c=1;c<=d;c++)	{	Response.Write(Request.Cookies(b)(c) + " ")	}	Response.Write("<BR>\r")	}	else	{	Response.Write(Request.Cookies(b) + "<BR>\r")	}	}
%>
</HTML>

Click Here to run the script in a new window.

We do the same job three times. You decide for yourself which one you like best. In the first example you can plainly see from the script, I ask a VBScript function to find and break down all the cookies. I then output the data back to the waiting JavaScript variable. 

var longCookie = forEachCookie()

What can I say? Don't lose track of your cookies and don't lose track of your Keys. Otherwise you might have to get a VBScript slim jim.

The new Enumerator() is okay. I use Enumerator two different ways; one way fails to capture the Key names, and the other way successfully captures the key names (but it needs unescape() to get the Key values to print normally).

In round three, I use a pair of for loops, but they're not as functional as for/in would be. (Notice the lack of Key names.)

Misc. Notes:

We didn't use new String( ) in this lesson. But remember, if you want to manipulate the cookie values inside JavaScript functions or methods, then you will need new String(). 

var firstCookie = new String(Request.Cookies("firstCookie") )
firstCookie = firstCookie.toUpperCase()

Also, if you were to use Client Side scripting to locate cookies, you would have noticed that there is an extra cookie. ASP keeps track of its sessions using a cookie.