javascript asp教程第九课--cookies

所属分类: 网络编程 / ASP编程 阅读数: 1517
收藏 0 赞 0 分享

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.

更多精彩内容其他人还在看

asp中去除内容HTML标签的三个function函数

asp中去除内容HTML标签的三个function函数
收藏 0 赞 0 分享

chr(9)、chr(10)、chr(13)、chr(32)、chr(34)讲解

chr(9)、chr(10)、chr(13)、chr(32)、chr(34)讲解
收藏 0 赞 0 分享

方便的大家admin及admin888 经过 md5加密后16位和32位代码

方便的大家admin及admin888 经过 md5加密后16位和32位代码
收藏 0 赞 0 分享

可用的ASP无重复数字随机函数, 数组实现, 并应用于随机显示记录集

可用的ASP无重复数字随机函数, 数组实现, 并应用于随机显示记录集
收藏 0 赞 0 分享

asp动态级联菜单代码

asp动态级联菜单代码
收藏 0 赞 0 分享

ASP中经常使用的SQL语句与教程说明

ASP中经常使用的SQL语句与教程说明
收藏 0 赞 0 分享

实例分析之用ASP编程实现网络内容快速查找的代码

实例分析之用ASP编程实现网络内容快速查找的代码
收藏 0 赞 0 分享

服务端 VBScript 与 JScript 几个相同特性的写法与示例

服务端 VBScript 与 JScript 几个相同特性的写法与示例
收藏 0 赞 0 分享

ASP 环境下 VBS 事件应用 示例代码

ASP 环境下 VBS 事件应用 示例代码
收藏 0 赞 0 分享

asp 之上传漏洞终结篇

asp 之上传漏洞终结篇
收藏 0 赞 0 分享
查看更多