System ServerRequest Variables

When your ASP script starts running, it has quite a number of system variables that help it perform tasks based on the browser the user is using, the type of computer they are running on, the language accepted, and much more. You can then customize your HTML so that it is just perfect for IE, or perfect for Netscape, or uses fonts for a Macintosh, and much more.

Here are some commmonly used server variables.

Variable NameFunction
HTTP_USER_AGENTBrowser the user is running
HTTP_UA_OSOperating system the user is running
HTTP_ACCEPT_LANGUAGELanguage the user wants
REMOTE_HOSTIP address of the user
GET_METHODGET or POST
HTTP_REFERERThe previous page the user came from

For example, here is a block of code that writes out the appropriate stylesheet entry to the page based on which type of browser the user is running.

Dim ServerVar
Set ServerVar = Request.ServerVariables
BrowserName = ServerVar(“HTTP_USER_AGENT”)
OpSys = ServerVar(“HTTP_UA_OS”)

‘SHOW STYLESHEET FOR MATCHING SYSTEM’
if InStr(BrowserName, “MSIE”) > 0 and InStr(BrowserName, “Win”) > 0 then
Response.Write “<link rel=’stylesheet’ href=’/_css/windows/ie.css’>”
end if
if InStr(BrowserName, “MSIE”) > 0 and InStr(BrowserName, “Win”) = 0 then
Response.Write “<link rel=’stylesheet’ href=’/_css/mac/ie.css’>”
end if
if InStr(BrowserName, “MSIE”) = 0 and InStr(BrowserName, “Win”) > 0 then
Response.Write “<link rel=’stylesheet’ href=’/_css/windows/netscape.css’>”
end if
if InStr(BrowserName, “MSIE”) = 0 and InStr(BrowserName, “Win”) = 0 then
Response.Write “<link rel=’stylesheet’ href=’/_css/mac/netscape.css’>”
end if

ASP Basic Concepts