javascript asp教程第八课--request对象 |
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Request Object: Request has five (5) Collections, one (1) Property, and one (1) Method. Youll use the Collections far more than the property or the method. Request Collections: Below is a table of the Request Collections and descriptions of how they are used.
ClientCertificate: Request.ClientCertificate is used with S.S.L. (Secure Sockets Layer). It is beyond the scope of this web site. Cookies: We will learn Request.Cookies and Response.Cookies together in Lesson 08. Please be patient. Form: Request.Form is probably the workhorse of the Request Collections. The first script is a repeat from Lesson 03. <%@LANGUAGE="JavaScript"%> <% //No ASP Here, just a regular HTML Page %> <HTML> <STRONG>Type something into the text box and submit it.</STRONG> <FORM ACTION="script08a.asp" METHOD="Post"> <INPUT TYPE="Text" NAME="WebPageVariable"><BR> <STRONG>How Much Money do you make each month?</STRONG><BR> <SELECT NAME="monthlySalary"> <OPTION>Under $5,000,000</OPTION> <OPTION>Above $5,000,000</OPTION> <OPTION>Nobodys darn business.</OPTION> </SELECT><BR> <INPUT TYPE="Submit" VALUE="Submit"> </FORM> </HTML> Click Here to run script08.asp in a new window. It posts information to script08a.asp which is found below. In turn, script08a.asp posts information to script08b.asp which is also found below. <%@LANGUAGE="JavaScript"%>
<%
var WebPageVariable = new String( Request.Form("WebPageVariable") )
WebPageVariable = WebPageVariable.toUpperCase();
var monthlySalary = new String( Request.Form("monthlySalary") )
monthlySalary = monthlySalary.toLowerCase();
%>
<HTML>
The Web Page Variable you typed is: <%=WebPageVariable%> <BR>
The monthly salary you listed is: <%=monthlySalary%> <BR>
<FORM ACTION="script08b.asp" METHOD="Get">
<INPUT TYPE="hidden" VALUE="<%=monthlySalary%>" NAME="QueryVariable">
<STRONG>Click the button to see Query Strings</STRONG><BR>
<INPUT TYPE="submit" VALUE="Submit">
</FORM>
</HTML>
Well be using Request.Form when we "Post" an HTML form to the server. Notice that the NAME attribute in the HTML form corresponds to the "name" in QueryString: Well be using Request.QueryString when we use an HTML form to "Get" a page from the server. Request.QueryString() is very similar to Request.Form(). Take a look at script08b.asp which I printed below. <%@LANGUAGE="JavaScript"%>
<%
var QueryVariable = new String( Request.QueryString("QueryVariable") )
%>
<HTML>
The QueryString Value is: <%=QueryVariable%> <BR>
<%
if (QueryVariable != "Lesson 08s new Query!")
{
QueryVariable="Lesson 08s new Query!"
QueryVariable=escape(QueryVariable)
%>
<A HREF="script08b.asp?QueryVariable=<%=QueryVariable%>">Click Here</A>
for the link to <I>script08b.asp?QueryVariable=<%=QueryVariable%></I>
<%
} //closing bracket for if statement.
%>
</HTML>
If you havent already, Click Here to run script08.asp in a new window. Cycle through all the forms and links, and then come back. You can use Request.QueryString in two different ways. You can either use an HTML form to "Get" a page from the server, which will generate a query string. Or you can manually build a query string and add it to the backside of a link. Well dissect script08b.asp from top to bottom. var QueryVariable = new String( Request.QueryString("QueryVariable") )
The line above in script08b.asp corresponds to the line below from script08a.asp <INPUT TYPE="hidden" VALUE="<%=monthlySalary%>" NAME="QueryVariable"> The NAME="someName" in the HTML form becomes the About half way into script08b.asp are the lines I reprinted below. <%
if (QueryVariable != "Lesson 08s new Query!")
{
QueryVariable="Lesson 08s new Query!"
QueryVariable=escape(QueryVariable)
%>
Weve already converted Request.QueryString() into a JavaScript string at the top of the script. So, now we can do a string comparison. If the QueryVariable hasnt already been set equal to "Lesson 08s new Query!" then we do that. Then we use the In lesson 14 well see a better way to encode URLs. When we study the Server Object, well see Server.URLEncode(). But for now, just know that escape() works. You can have more than one QueryString on each page. If you lose count of your QueryStrings, then you use The Request Shortcut: Request.Form() and Request.QueryString() share a shortcut. ServerVariables: Server Variables represent the HTTP Headers sent to the server by the client. I wont demonstrate them all, because there are too many. <%@LANGUAGE="JavaScript"%>
<HTML>
<TABLE BORDER="1">
<TR><TD>ALL_RAW</TD>
<TD><%=Request.ServerVariables("ALL_RAW")%></TD></TR>
<TR><TD>REMOTE_ADDR</TD>
<TD><%=Request.ServerVariables("REMOTE_ADDR")%></TD></TR>
<TR><TD>HTTP_USER_AGENT</TD>
<TD><%=Request.ServerVariables("HTTP_USER_AGENT")%></TD></TR>
<TR><TD>URL</TD>
<TD><%=Request.ServerVariables("URL")%></TD></TR>
</TABLE>
</HTML>
Click Here to run the script in a new window. Demonstrated above are four (4) server variables. There are (give or take) about 50 server variables available. You can look up the full list of server variables for yourself on the internet. Misc. Notes: Request.BinaryRead() is the lone method and TotalBytes is the lone property. |
