ECommerce Infrastructure

1
E-CommerceInfrastructure Security

• Lecture 8
• Advanced VB Script

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Answering Your Question

• ltform namefmrOuttergt
• ltINPUT TYPE"TEXT" NAME"OutterText" SIZE"20"
  MAXLENGTH"8"gtltbrgt
• lthrgt
• ltFORM NAMEfrmInnergt
• ltINPUT TYPE"TEXT" NAME"InnerText"
  SIZE"20" MAXLENGTH"8"gtltbrgt
• ltINPUT TYPE"reset"gt
• lt/formgt
• lthrgt
• ltINPUT TYPE"TEXT" NAME"OutterText2"
  SIZE"20" MAXLENGTH"8"gtltbrgt
• ltINPUT TYPE"reset"gt
• lt/formgt

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Multiple Forms

• You cant embed forms inside each other
• You can have more than one form on an html page

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Agenda

• VB Script - Validating Users Input

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Validating Users Input

• So weve got a form
• The user types in a bunch of information
• Then the user clicks SUBMIT
• This data will be transferred to the server
• Why not just test it on the server?

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Motivation

• Why require the trip across the network?
• Latency
• Server load
• Keep it on the client
• Increases speed
• This is what client-side scripting is for

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Two-Part Process

• Certainly we dont want garbage coming to us
• Lets check the format of the input and then give
  a warning if its not correct
• Wed also like to shift focus to the incorrect
  element

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What If There Is More than One Error?

• Certainly there could be more than one error
• Some different policies
• Handle the first and stop
• Show a message indicating all errors

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The Better Approach

• Showing everything might seem appropriate - more
  information
• But users can get overwhelmed quite easily
• So were going to handle the errors one at a time

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Creating the Form

• Open FrontPage, Dream Weaver, etc.
• Were going to create a form together
• Then well add the VBScript to validate the input

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What the Form Must Contain

• First Name
• Last Name
• Telephone number
• Cell Phone Number
• Birthday
• Notes

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The Final Product
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Now Lets Create the VBScript

• Well need a few different functions
• Validate that inputs arent empty
• All but the cell phone notes will be required
• Validate that phone number birthday are entered
  correctly
• Use a message box to show error

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Make Sure the Entry is Present

• Function IsEmpty(toCheck)
• if toCheck.Value then
• MsgBox Please fill in a value for _
  toCheck.text, vbCritical, _
• Missing Info toCheck.name
• IsEmpty true
• else
• IsEmpty false
• end if
• End function

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Validating a Phone Number

• Function ValidPhone(toCheck)
• assumes that toCheck isnt empty (check before)
• Dim regularExpression
• Set regularExpression new RegExp
• regularExpression.pattern \d3-\d3-\d4
  
• if (not regularExpression.Test(toCheck.Value))
  then
• MsgBox Please use the -- format
  for _ toCheck.text, vbCritical, _
• Invalid phone number entered
  toCheck.name
• ValidPhone false
• else
• ValidPhone true
• end if
• End function

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Regular Expressions

• - beginning of string
• h will match hello but not ohio
• - end of string
• b will match crib but not bed
• n matches repeats of preceding
• a2 matches aa, baah, but not eat
• \d matches any digit
• \d will match 1, 2, 3, etc.

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Regular Expressions (cont)

• \d3-\d3-\d4
• Matches 3 digits followed by - and three more
  digits followed by - and four digits
• Does not allow other characters before or after

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Validating a Birthday

• Function ValidBDay(toCheck)
• assumes that toCheck isnt empty (check before)
• Dim regularExpression
• Set regularExpression new RegExp
• regularExpression.pattern \d2/\d2/\d4
  
• if (not regularExpression.Test(toCheck.Value))
  then
• MsgBox Please use the MM/DD/YYYY format for
  _ toCheck.text, vbCritical, _
• Invalid birthday entered toCheck.name
• ValidBDay false
• else
• ValidBDay true
• end if
• End function

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Putting It All Together

• function ValidateInformation
• dim rv
• rv True
• if IsEmpty(Document.UserInput.FirstName) then
• rv false
• elseif IsEmpty(Document.UserInput.LastName)
  then
• rv false
• elseif IsEmpty(Document.UserInput.TelephoneNumbe
  r) then
• rv false
• elseif not ValidPhone(Document.UserInput.Telepho
  neNumber) then
• rv false
• elseif not (Document.UserInput.CellPhoneNumber.V
  alue "") then
• if not ValidPhone(Document.UserInput.CellPhone
  Number) then
• rv false
• end if
• elseif IsEmpty(Document.UserInput.Birthday)
  then
• rv false
• elseif not ValidBDay(Document.UserInput.Birthday
  ) then

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Not Done Yet!

• This works well, but
• When the user makes a mistake, wed like to put
  focus on the thing that needs to be changed
• Can we focus the form element?

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Changing Focus

• The focus method shifts the browsers attention
  to the object
• i.e. ltform elementgt.Focus
• ex. Document.UserInput.FirstName.Focus

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Where To Apply This

• Any time in this course in which you are asking
  the user for specific information with
  constraints
• Of course, we can do better than this
• ActiveX (date pickers, etc.)
• OnChange event for Text or TextArea

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Project 3 Is Due Tuesday _at_ 6pmFind a Group for
Project 4
FIN