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This is your ASP Cheat Sheet!

General -- general information, including tutorial websites
Built-in Methods -- ways to communicate with the outside world
Text Manipulation -- including encapsulation (quoting)
Math -- and other functions
Flow of control -- ifs, loops, functions, etc.
Email -- sending email from an ASP script

General -- general information

Tutorial and Reference Websites

ASP Tutorial For Beginners

General syntax

When you save a web page, name it something.asp to tell the server it contains ASP code.

The default scripting language is VBScript.  To use JavaScript for ASP code, start the page with
   <%@ language="javascript"%> (not recommended, since this cheat sheet assumes VBScript)

Enclose ASP code in <% and %> -- everything in between is executed, and then the server replaces it with the output of running the program.

Upper/lower case in built-in methods seems not to matter; however good form is to "properize" all names

' Comments are set off by a single quote

Continuation: end each line but the last with underscore _

<!--#include file="filename.asp" -->
<!--#include virtual="filename.asp" --> -- includes the file (or virtual file).  Can only be used outside <%, %> delimiters. 

Constants:
   string -- "value"
   hex number -- &hFF00FF (Magenta) -- note: colors are in reverse order BGR
   vbNewLine -- platform-specific newline character (Chr(10) or Chr(13)&Chr(10))
   date -- #May 10,2002#

Declaring a variable:
   dim names(6),i -- declares an array variable, names, and a scalar variable, i.  Later, use it this way:
   For i = 0 to 6 : response.write(names(i) & "<br />") : Next

Variable scope
   variables declared outside a procedure are can be accessed and changed by any procedure in the ASP file.
   variables declared in a procedure are created and destroyed each time the procedure is entered/exited.
   Session variables -- used to store information about ONE single user, and are available to all pages in one application. Typically information stored in session variables are name, id, and preferences
   Application variables -- also available to all pages in one application. Application variables are used to store information about ALL users in a specific application.

Variable type -- returned by VarType(variable) --
   0 - vbEmpty -- Empty (uninitialized) 
   1 - vbNull -- Null (no valid data) 
   2 - vbInteger -- Integer 
   3 - vbLong -- Long Integer 
   4 - vbSingle -- Single-precision floating-point number 
   5 - vbDouble -- Double-precision floating-point number 
   6 - vbCurrency -- Currency 
   7 - vbDate -- Date 
   8 - vbString -- String 
   9 - vbObject -- Object 
   10 - vbError -- Error 
   11 - vbBoolen -- Boolean 
   12 - vbVariant -- Variant (Used only with Arrays) 
   13 - vbDataObject -- Data-access Object 
   17 - vbByte -- Byte 
   8192 - vbArray -- Array

Built-in Methods -- ways to communicate with the outside world

response

response.buffer=true -- Use at the top of an ASP page. It means: Don't start sending the page until it is completely built. This is needed if response.redirect might be used later!

response.write text -- text is written to the user's browser, replacing the ASP code in the page

response.redirect "http://" & v1 & v2 & v3 & v4 & v5 & v6 & v7 Redirect to another web page

Response.Cookies("cookiename").Expires=date+365 -- make the cookie, "cookiename", expire in one year
   Note: The Response.Cookies command must appear BEFORE the <html> tag.
Response.Cookies("cookiename")=value -- store value in cookie, "cookiename".
Response.Cookies("cookiename")("keyname")=value -- store value in key "keyname" of cookie, "cookiename".

request

v1=request.querystring("v1") -- In "get" mode, get the value of the parameter, v1 that was sent via http://webpage&v1=value&v2=value
   use: if v1<>"" then : ... to see if the variable was supplied

v2=Request.Form("fname") -- In "post" mode, get the value of the parameter, v2, that was sent via a form.
   use: if v2<>"" then : ... to see if the variable was supplied

Request.ServerVariables ("HTTP_User-Agent") client browser type as a string. 
Request.ServerVariables ("REMOTE_ADDR") client's IP (Internet protocol) address as a string. 
Request.ServerVariables ("REMOTE_HOST") client's domain name as a string. 
Request.ServerVariables ("SERVER_NAME") domain name of the server as a string. If the server has no domain name, returns the server's IP address as a string.
Request.ServerVariables("HTTP_REFERER") web page that directed you to this page -- very handy for email scripts!
For Each Key in Request.ServerVariables : response.write Key & ": " & request.servervariables(Key) & " <br><br>" : Next -- a complete little program that lists the names and values of all the server variables

cookievalue=Request.Cookies("cookiename") -- get the value of the cookie, "cookiename"
For Each x In Request.Cookies
   If Request.Cookies(x).HasKeys Then '-- test whether each cookie has keys
      Response.Write("<p>")
      For Each y in Request.Cookies(x)
         Response.Write(x & ":" & y & "=" & Request.Cookies(x)(y)) & "<br />"
         Next
   Else
      Response.Write(x & "=" & Request.Cookies(x) & "<br />")
   End If
   Response.Write "</p>"
   Next

Session

Session.Timeout=5 -- sets timeout to 5 minutes (default is 20 minutes)
Session.Abandon -- causes a session to end
Session("variablename")=value -- stores value in session variable, "variablename".
x=Session("variablename") -- returns value of session variable, "variablename".
For Each x in Session.Contents : Response.Write "Session variable " & x & " = " & Session.Contents(x) & "<br>" : Next
Session.Contents.Count -- returns the number of session variables
Session.Contents.Remove("variablename") -- removes a session variable
Session.Contents.RemoveAll() -- removes all session variables
For Each x In Session.StaticObjects : Response.Write(x & "<br />") : Next -- see all the session objects

Application and global.asa

Application variables are created in global.asa this way:
   <script language="vbscript" runat="server">
      Sub Application_OnStart : Application("vartime")="" : Application("users")=0: End Sub
      Sub Application_OnEnd: code to clean up after last user : End Sub
      Sub Session_OnStart : Application.Lock : Application("users")=Application("users")+1 :
         Application.Unlock : Session("started")=now() : End Sub
      Sub Session_OnEnd: Application.Lock : Application("users")=Application("users")-1 :
         Application.Unlock : End Sub
   </script>
Application("variablename") -- returns value of variable, "variablename"
Application.Contents.Count, etc., work just as Session.Contents.Count, etc.
Application.Lock -- prevents other users changing the application's variables
Application.Unlock -- allows other users changing the application's variables 

Text Manipulation, encapsulation (quoting)

Built-in Functions

Asc(char), AscW(char) -- returns the ascii (or Unicode for AscW) value of the given character.
Chr(n), ChrW(n) -- returns the character whose ascii code is n.
InStr(n,hay,needle,C), InStrRev(hay,needle,s,C) -- 1-based position (at or after optional position n) of the first (last)
   occurrence of  needle within haystack or 0 if not found;    (C=0 for binary, C=1 for text-base comparison)
   Ex: InStr(3,"abcdef","cde")=3.  InStr(100,"abcdef","cde")=0.  Instr(0,"abcdef","cde")=Error
         InsStrRev(4,"abcdef","cde")=0.  InsStrRev(5,"abcdef","cde")=3. 
LCase(s), UCase(s) -- lower case (upper case).
Len(s) function is used to determine the length or number of characters in a string.
Left(s,n), Right(s,n) -- a number of leftmost (rightmost) characters of string s.
Mid(s,n,l) -- returns the middle characters starting at 1-based position n, length l.  l=0 ok, l>Len(s) ok, n=0 Error, n>Len(s) ok.
LTrim(s), RTrim(s), Trim(s) function is used to remove leading / trailing / both spaces from a string.
Replace(hay,needle,replacement,n,c,C) -- replace a specified substring (optional position n, count c, compare-type C)
Space(n) -- creates a string including the specified number of spaces.
StrComp(string1,string2,C) function compares two strings and returns whether they are equal or not.
String(n,c) -- String of n c's.  If c is string, only first character is used.
   Tip: to create multiple instances of a longer string, use Replace(String(3,"a"),"a","elephant")
StrReverse(s) -- creates a string in which the character order of a specified string is reversed.

Server Methods

Server.MapPath("readmetest.txt") -- converts virtual file to fully qualified server filename

Math and other built-in functions

Prime number example

operators, expressions

eval(expression), (expression) -- evaluates the expression; needed with & for concatenation
n = expression -- assignment
a+b, a-b, a*b, a/b, a^b -- addition, subtraction, multiplication, division, exponentiation
a\b -- integer division

logical expressions, used in: if expression then : statements : end if

a=b, a<b, a<=b, a>b, a>=b, a<>b -- evaluate to vbTrue is -1; vbFalse is 0
a And b, a Or b, a Xor b -- bitwise and, or, exclusive or.  "And" binds tighter than "Or", so use parentheses
Not a -- bitwise negation of a

time and date

t=Now() -- returns time of day
Hour(t) -- returns hour of day, from 0 to 23

other math functions

Abs(n) -- absolute value of n
Sgn() function is used to determine the sign of a number, i.e. whether it is greater than, equal to, or less than zero.
Sqr() function takes a number and calculates the square root.
Fix(n), Int(n), Round(n,d) -- next-smaller, next-lower, or nearest: Int(6.2) is 6; Int(-6.2) is -7; Fix(-6.2) is -6; Round(3.14,1)=3.1.
Randomize, Rnd(), Rnd(n) -- seed the random number generator, next random number between 0 and 1,
   Rnd(0)=same number again, Rnd(n) with n<0 = a particular number using n as the seed
Abs(n) function returns the absolute value of a number, i.e. its unsigned magnitude.
Cos(n), Sin(n), Tan(n), Atn(n) function computes the trig function (angle in radians)
Exp(n), Log(n) function returns e (the base of natural logarithms) raised to a power, and the natural log
FormatNumber(n,p,z,n,g), FormatCurrency(n,p,z,n,g), FormatPercent(n,p,z,n,g) --
   format n with precision p, tristate z for leading zero, tristate n for negative parens, tristate g for comma grouping.
   (tristate: 0=false, -1=true, -2=use VB default)
Hex(n), Oct(n) function converts a number or expression to a string representing the hex (or octal) value.
RGB(r,g,b) returns r + 256g + 65536b

Flow of Control -- if's, loops, functions, etc.

If logicalexpression Then : statements : Else : statements : End If

Do While...Loop -- Do While n < 10 : response.write n : n=n+1 : Loop
Do Until...Loop -- Do Until n = 10 : response.write n : n=n+1 : Loop
Exit Do -- (And Exit For, Function, Property, or Sub) leaves the enclosing loop or other unit.
For n=1 to 20 Step 2 : response.write n : Next n -- the variable after "Next" is optional.
   test is done first, so For n=2 to 1 will not even run once
   after the loop is done, n will have been incremented (n=21 in this case)
For Each x --
   Dim names(2) : names(0) = "Al" : names(1) = "Bo" : names(2) = "Cal" : For Each x In Names : Response.Write(x & "<br />") : Next
Select Case x : Case "Al" : stmt : Case "Bo" : stmt : Case Else : stmt : End Select

Sub vbproc(num1,num2) : response.write(num1*num2) : End Sub
call vbproc(3,4)

Function vbfunc(a) : vbfunc=returnvalue : End Function
x=vbfunc(3)

Email -- sending email from an ASP script

Bamboo Example -- sends a message to "feedback" (so it goes into the bit bucket).  This has a problem that the encoding is not text/html, so the html doesn't format the text as expected.

JMail Example -- sends a message.  JMail also has the ability to behave as a POP3 client to receive messages, read them, and act on their contents.

For more info: JMail Reference