Website Development

1
Website Development Management
MIS 3353 -- Fall 2002

• Server-Side Scripting Using Active Server Page
  Technology

Instructor John Seydel, Ph.D.
2
Student Objectives

• Create server-side confirmation pages
• Discuss what happens when browser and server
  interact for web page delivery
• Differentiate among the various VBScript data
  subtypes
• Use appropriate variable naming conventions
• Summarize useful VBScript string, date, math, and
  conversion functions
• Compare and contrast subroutines and functions
• Use If . . . Then . . . Else contruct for
  branching
• Be familiar with Select . . . Case construct
  applications
• Use For . . . Next and Do While contructs for
  looping
• Understand the use of the Response and Request
  objects for basic ASP output and input

3
First, Some Administrative Stuff

• Exam 2
• Grading
• Part 1 (written portion)
• 67 points possible
• Highest raw score 64
• Raw scores adjusted
• Minimum 53 (my work)
• Scores above raised (split the difference)
• Part 2 (online portion)
• 33 points possible
• Everyone who tried received full points for Part
  2
• Return exams (and recent quiz)
• Questions concerning homework?

4
A Look at the Guestbook Form Handler

• Values collected by guestbook controls
• Text box txtName
• Radio buttons optGender
• Select box cmbAge
• Check boxes chkFTStudent, chkFTJob, chkBurnout
• Basic form handler
• Simply confirms what was sent
• Starts with an HTML page with blanks left in it
  for data
• Needs then to access data sent as part of Form
  collection
• Use Request.Form()
• Assign results to variables
• Then fills in the blanks within the HTML page
  using Response.Write
• Coming soon updating and accessing the database

5
Some Things to Note About the GuestBook Form
Handler

• Look at complete code
• Option Explicit
• Forces variables to be declared
• Must be very first statement of code (before XML
  declaration)
• Generally optional where scripting takes place
  recommendation
• Document head preliminary processing
• Within document on-demand processing
• Could have used Response.Write to have the server
  write all or part of the HTML (recommended by
  text)
• Recommendation for this class write as much as
  possible of the HTML without relying on the
  server to write it
• More intuitive because of familiarity with HTML
• Works better when HTML editor is being used

6
Input and Output with ASP

• Two important server objects are involved here
• Request
• Response
• These objects have numerous uses via their
• Properties
• Methods (i.e., functions and subroutines)
• For now lets consider only input/output
• Getting information (input) Request object
• Access the Form, QueryString, or ServerVariables
  collections (collections are like arrays)
• Gathers data from those collections
• Sending information (output) Response object
• Call the Write method (a subroutine)
• Writes information to the web page being sent to
  client

7
What Happens When You View a Web Page?

• Consider figure on p. 60 (or p. 16 in XHTML text)
• Two ways to request resources
• Click on a link
• Type a URL into address bar
• HTTP request is then sent to server at designated
  URL
• Includes header info
• Requests file
• Server processes file
• If htm extension, then just sends file with
  response
• If asp extension, then script is processed first
• Server then returns HTTP response
• Includes header info
• Contains files (HTML and others, e.g., images)

8
HTTP Request Example

• Request
• GET/index.html?namejuliesmithID12234
• /HTTP/www.astate.edu
• /HTTP1.1
• Header
• Useragent IE 5.0
• Accept /
• Date 10/24/02
• Body
• (empty)

9
HTTP Response Example

• Response
• HTTP1.1/200
• Header
• Server IIS 50
• Date 10/24/02
• Body
• lthtmlgt
• . . .
• lt/htmlgt

10
ASP and VBScript

• ASP is a server-side processing technology by
  Microsoft
• Will interpret programming instructions in
  several languages
• JScript (MS implementation of JavaScript)
• VBScript the de facto language for ASP
• Others
• ASP code is delimited by lt and gt
• VBScript
• Uses same syntax as VB
• Most of the data types and functionality for VB
  are available to VBScript
• Therefore, a good reference for VBScript is any
  text on VB

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Before Going Further, Lets Consider Data Subtypes

• VBScript automatically determines data subtype
  based upon variable contents
• Typical subtypes well be using
• Numeric
• Integer
• Long
• Double
• String
• Date
• Boolean
• Why worry?
• We need to be aware of data subtype in order to
  manipulate (math operations, string processing, .
  . . )
• Use the appropriate conversion functions

12
Variable Naming Conventions

• Variable names based upon data type
• First three characters in lower case
• Words starting in upper case
• Common names (see table on page 137)
• String (e.g., strFirstName)
• Integer (e.g., intAge)
• Double (e.g., dblBMI)
• Long (e.g., lngStatePopulation)
• Boolean (e.g., blnHealthy)
• Date (e.g., datPurchase)

13
Data Conversion Functions

• Form data will often be interpreted by VBScript
  as text and must converted for arithmetic to be
  performed
• Also data from a database can be of numerous
  types and must often be converted
• For best results, use conversion functions (see
  p. 145)
• CStr()
• CInt()
• CLng()
• CDbl()
• FormatCurrency()
• Note just naming a variable per the
  conventions, doesnt make the data contained
  conform to the name
• Example intAmount More money!
• Doesnt convert to integer

14
A Little Bit on Functions, Subroutines,
Arguments

• Arguments (called parameters) are the values
  brought into and used in the subprocedure
• Syntax for subprocedures
• Functions (return values)
• Defining FunctionName(arg1,arg2, . . .)
• Calling Variable FunctionName(arg1,arg2, . .
  .)
• Example strTotalPrice FormatCurrency(dblPrice,
  2)
• Subroutines (dont return values)
• Defining SubroutineName(arg1, arg2, . . .)
• Calling Call SubroutineName(arg1, arg2, . . .)
• Example Call Response.Write(strName)

15
A Digression Some Shortcuts

• Note equivalence
• Call Response.Write(strName)
• Response.Write(strName)
• Response.Write strName
• If only one statement is involved the following
  are also equivalent
• lt Response.Write strName gt
• lt strName gt
• If data are coming only from a single source or
  multiple sources with no duplicate names, the
  following are equivalent
• Request.Form(txtName)
• Request(txtName)

16
Intrinsic Functions

• Many built-in (intrinsic) functions come as part
  of VB (and VBScript)
• Some categories are
• Date Time
• String Manipulation
• Numeric
• Its important to be familiar with these
• That they exist
• Where to find information about them

17
Handy Date/Time Functions

• Time
• Date
• Now -- returns both date and time
• Day(date) -- returns day portion of date string
• Month(date) -- returns month portion of date
  string
• Year(date) -- returns year portion of date string
• Weekday(date) -- returns day (1-7) of the week
• WeekdayName(number) -- returns day (e.g., Monday)
  for given weekday (1-7)
• MonthName(number) -- returns month (e.g., March)
  for given month number (1-12)
• DateDiff(date1,date2) -- returns number of days
  difference
• DateAdd(date,number) -- returns new date

18
String Functions

• Some of the more useful ones
• InStr(search,target) -- returns starting position
• Len(string) -- returns length of string
• LCase(string) -- converts case
• LTrim(string) -- trims blanks at left
• Trim(string) -- trims blanks at both ends
• String(n,character) -- returns n characters
• Left(string,n) -- returns left n characters
• Mid(string,x,n) -- returns n characters starting
  at x
• An example the original guestbook form handler

19
Math Functions

• Ones well likely use
• Rnd -- needs to be preceded by call to Randomize
• Int(x) -- truncates beyond decimal point
• Round(x) -- rounds to nearest whole number
• Some of the others that exist
• Exp(x)
• Log(x)
• Sqr(x)
• Fix(x)
• . . .

20
Control Structures in VBScript

• Recall the framework weve been dealing with
• Sequence
• Selection (per the text, branching)
• Looping
• Now, (per the text) add jumping
• Often a form of selection
• Involves subprocedures
• Functions
• Subroutines

21
Branching Structures

• VBScript
• If . . . Then . . . Else
• Select . . . Case
• Similar in usage to their JavaScript counterparts

22
Syntax for If . . . Then . . . Else

• Consider original guestbook form handler
  (determining Mr./Ms prefix)
• VBScript syntax
• If condition Then
• . . . what to do if true . . .
• Else
• . . . What to do if false . . .
• End If
• Compare to JavaScript
• if (condition)
• . . . what to do if true . . .
• else
• . . . What to do if false . . .

23
Syntax for Select . . . Case

• Use instead of If . . . Then . . . Else when many
  possible branches
• VBScript
• Select Case varname
• Case value1
• What to do
• Case value2
• What to do
• . . .
• Case Else
• What to do
• End Select
• Compare with JavaScript
• switch (varname)
• case value1 what to do
• case value2 what to do
• . . .
• default what to do

24
Looping Structures

• Enable repetitive ifthenelse processing
• Several options exist well be using
• For . . . Next loops
• Do . . . While loops
• As with JavaScript,
• Automatic incrementing takes place with For loop
• Must have something to cause Do loop to terminate
• Consider form processing of records from a
  database (e.g., guestbook database)

25
For . . . Next Loops

• VBScript
• For counter startvalue To stopvalue Step
  increment
• . . . statements . . .
• Next
• Compare with JavaScript
• for (start terminal condition step)
• . . . statements . . .

26
Do . . . While Loops

• VBScript
• Do While condition
• . . . statements . . .
• Loop
• Compare with JavaScript
• while (condition)
• . . . statements . . .

27
Review/Demo of ASP Application Development

• Must be tested on a server
• Actual server (AITP), running IIS
• Possibly local IIS if running Win2000
• Recommended process
• Write code locally
• Upload
• Test
• Modify locally
• Upload new version
• Test
• Repeat as necessary

28
Student Objectives

• Create server-side confirmation pages
• Discuss what happens when browser and server
  interact for web page delivery
• Differentiate among the various VBScript data
  subtypes
• Use appropriate variable naming conventions
• Summarize useful VBScript string, date, math, and
  conversion functions
• Compare and contrast subroutines and functions
• Use If . . . Then . . . Else contruct for
  branching
• Be familiar with Select . . . Case construct
  applications
• Use For . . . Next and Do While contructs for
  looping
• Understand the use of the Response and Request
  objects for basic ASP output and input

29
Appendix
30
GuestBook Confirmation Plain XHTML with Blanks

• ltheadgt
• lttitlegtGuest Book Response for Suzy
  Studentlt/titlegt
• lt/headgt
• ltbodygt
• lth1 align"center"gtGuestbook Confirmationlt/h1gt
• lth3gtHere's the information you gave uslt/h3gt
• ltulgt
• ltligtName ltemgt xxx lt/emgtlt/ligt
• ltligtGender ltemgt xxx lt/emgtlt/ligt
• ltligtAge ltemgt xxx lt/emgtlt/ligt
• ltligtFull-time student ltemgt xxx lt/emgtlt/ligt
• ltligtWorking full-time ltemgt xxx lt/emgtlt/ligt
• ltligtGoing to school and working ltemgt xxx
  lt/emgtlt/ligt
• lt/ulgt
• lt/bodygt

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GuestBook Confirmation Getting Data

• ltheadgt
• lttitlegtGuest Book Response for Suzy
  Studentlt/titlegt
• lt
• Dim strName,strAge,strGender,strFTStu,strFTWork,
  strBurnout
• strGender Request.Form("optGender")
• strName Request.Form("txtName")
• strAge Request.Form("cmbAge")
• strFTStu Request.Form("chkFTStudent")
• If strFTStu ltgt "yes" Then strFTStu "no"
• strFTWork Request.Form("chkFTJob")
• If strFTWork ltgt "yes" Then strFTWork "no"
• strBurnout Request.Form("chkBurnout")
• If strBurnout ltgt "yes" Then strBurnout "no"
• gt
• lt/headgt

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GuestBook Confirmation Displaying Data

• ltulgt
• ltligtName ltemgtlt Response.Write strName
  gtlt/emgtlt/ligt
• ltligtGender ltemgtlt Response.Write strGender
  gtlt/emgtlt/ligt
• ltligtAge ltemgtlt Response.Write strAge
  gtlt/emgtlt/ligt
• ltligtFull-time student
• ltemgtlt Response.Write strFTStu gtlt/emgt
• lt/ligt
• ltligtWorking full-time
• ltemgtlt Response.Write strFTWork gtlt/emgt
• lt/ligt
• ltligtGoing to school and working
• ltemgtlt Response.Write strBurnout gtlt/emgt
• lt/ligt
• lt/ulgt

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Objects

• Characteristics
• Have properties (attributes that describe them)
• Do things
• Methods (i.e., behaviors or subprograms)
• Functions (return values)
• Subroutines
• Triggered by
• Events (e.g., onMouseOver)
• Direct calls
• Where do they come from
• Built in
• Browser objects (e.g., window)
• JavaScript objects (e.g., Math)
• ASP objects (e.g., Response)
• Need reference for properties and methods
• User-defined