CLIENTSIDE SCRIPTS

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CHAPTER 7

• CLIENT-SIDE SCRIPTS
• Khai Le

2
An Overview
3
Definition

• Scripts
• Source codes that is interpreted into machine
  language one line at a time
• Machine Language
• Binary language understood by computer

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TWO TYPES OF SCRIPTS

• Client-side
• Run on users computer
• Server-side
• Run on Web servers

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SCRIPTS EXAMPLES

• Client-Side Script
• JavaScript
• VBScript
• Server-Side Script
• Server-Side Includes (SSI)
• Active Server Pages (ASP)

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USAGE OF CLIENT SIDE SCRIPTS

• Primary usage is to validate user inputs entered
  on web (HTML) forms
• Other uses
• Cookies

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HTML FORMS

• HTML Form
• Enhanced HTML documents designed to collect user
  information and send them back to a server
• Create by a form ltINPUTgt tag in the HTML document

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HTML FORMS TYPES

• Input Box (text box)
• Radio or option button
• Selection list (list box)
• Submit command button
• Reset command button

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TYPE ATTRIBUTE OF ltINPUTgt TAG

• ltINPUT TYPETEXTgt
• Specify the input control is a text box where
  user input is displayed as it was entered
• ltINPUT TYPE PASSWORDgt
• Same as the text box but the characters are
  masked with special characters

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Cont.

• ltINPUT TYPECHECKBOXgt
• Specifies a check box control
• If CHECKED is included after the CHECKBOX then
  when the form is first displayed the checkbox
  control will be checked
• VALUE specifies the value of the checkbox of
  either On or Off

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Cont.

• ltINPUT TYPE RADIOgt
• Specify a radio or option button control
• If CHECKED is included then it will be selected
  when the form is first displayed
• VALUE specifies the value of the radio button

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Cont

• ltINPUT TYPEBUTTONgt
• Specifies a command button
• ONCLICK attribute specifies the name of a program
  that is called when the user click the command
  button
• VALUE attribute is used to specify a different
  caption instead of the defaulted Button

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Cont.

• ltINPUT TYPE SUBMITgt
• Specifies a command button with a Submit
  caption
• When click, all value of fields will be submitted
  as parameters to the form-processing program

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Cont.

• ltINPUT TYPERESETgt
• Specifies a command button with a Reset button.
• When click, all form control values are cleared
  and the form is returned to its default state
• VALUE attribute specify desired captions

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OTHER TAGS

• ltINPUT TYPEHIDDENgt
• Create a hidden form field invisible to user but
  can be used to submit data to the processing
  program. E.g. Date recording
• TEXTAREA Element Tags
• Specifies input box with multiple lines of text
  using ROW and COLS attributes

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Cont.

• SELECT Element Tag
• Specifies a list box
• Use SIZE attribute to control number of displayed
  item

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SCRIPTS

• Scripts can be used to perform data validation.
• Why use scripts?
• Faster to create
• Faster to modify
• Small size

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SCRIPTS

• PERL
• Practical Extraction and Report Language
• Developed in 1987 by Larry Wall
• Intended to be use as a UNIX operating scripting
  language
• Does not run in a Web browser
• Used only on server-side scripts

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SCRIPTS

• JavaScript
• Developed in 1995 by Netscape
• Originally designed for server-side
• Changed to client-side
• Syntax is similar to C, C, and Java but behave
  differently
• Often used in data validation and creating pop up
  windows

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SCRIPTS

• VBScript
• Used in client and server-side
• Used in scripting ASP
• Related to Visual Basic programming language
• Work best on Microsoft browser

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SCRIPTS

• ASP
• Contains script-processing and HTML command
• Processed on a Microsoft Web server
• Produced dynamic web page for users browser

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CREATING CLIENT-SIDE VBSCRIPT

• VBScript code is embedded in the header section
• ltSCRIPT LANGUAGEVBSCRIPTgt
• program lines
• lt/SCRIPTgt
• Need Microsoft s Browser to work

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DEBUGGING

• Remember to save your modified version
• View source code to determine whether it had the
  latest version
• Make sure the page is not cached
• Check the code lines

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CREATING COOKIES

• Cookie is a data file written to the users
  computer by a program in a Web page
• Contain information of visitors to web page
• A single cookie can contain 4096 characters

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TYPES OF COOKIES

• Temporary cookie
• Store info in main memory of users computer and
  valid only during active session
• Unavailable when user exits browser
• Associated with HTML document
• Stored as text strings.

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Cont.

• Persistent Cookies
• Store values which are available to future
  browsing sessions
• Same syntax as temporary but with an expiration
  date
• Maximum of 300 cookies in a users computer

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DISPLAY WEB PAGE USING CLIENT-SIDE SCRIPT

• Start a new browser session and open a new
  browser window with the new Web page displayed.
• Display the new Web page in the current browser
  window (pop up windows)

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DISLAYING A WEB PAGE IN A NEW BROWSER WINDOW

• Usually done when the new page is unrelated to
  the current page or does not share data
• Allow multiple windows for users to view
  simultaneously
• Format (VBScript)
• Window.Open URL, Target, Option List

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Cont.

• URL
• Address of the new page
• Target
• Name given to the new window
• Option List
• Specify the properties of the new browser window
  such as location, toolbar, status, scrollbar,
  resizable, width, height, etc.

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DISPLAY A WEB PAGE IN THE CURRENT PAGE

• Use the Navigate method to display a new Web page
  in the current browser window
• Format Navigate(Web page URL)
• Save space on taskbar
• No need to close multiple browser window

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SUMMARY

• Client-side script is uncompiled code that is
  compiled on the users computer
• Used primarily in data validation on HTML forms
• Script are small programs using languages such as
  PERL, JavaScript, VBScript, etc
• Cookies store information about a visitors visit
  to a web site

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THE END

• NO QUESTION PLEASE!!!