Client Side Scripting BICS546
Client Side Scripting BICS546. Client-Side vs Server-Side Scripting Client-side scripting: –The browser requests a page. –The server sends the page to.
Dec 22, 2015
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Client Side Scripting
BICS546
Client-Side vs Server-Side Scripting
• Client-side scripting:– The browser requests a page.– The server sends the page to the browser.– The browser sends the page to the script engine.– The script engine executes the script.
• Server-side scripting:– The browser requests a page.– The server sends the page to the engine.– The script engine executes the script.– The server sends the page to the browser.– The browser renders the page.
HTTP Protocol (.Net p82)
• HTTP Request– Request line: HTTP method, file name, and HTTP
version.
– HTTP Header: acceptable file types, browser type, etc.
– HTTP Body: data sent to the browser.
• HTTP Response– Response line: HTTP version, status code.
– HTTP header: server info, info about data being sent.
– HTTP Body: HTML code
HTML Introduction
• Heading section– <head>, <title>, <meta>, <script>, etc.
• Body section– <body>, <p>, <h1> to <h6>, <a>, <br>– Formatting: <b>, <I>, <u>, <center>– Comment: <!-- comment -->– List <ul>– Image– Table: <table>, <tr>: a new row in table, <td>: a new cell in
a table row.– Form: <form>, <input>, <select>, <textarea>
Webpage Editor
• FrontPage demo
• Microsoft Script Editor
META Tag
• The meta tag allows you to provide additional information about the page that is not visible in the browser:– <meta name=“Author” content=“D Chao”>– <meta name=“Keywords” content=“apple,
orange,peach”>
• Redirection:– <meta http-equiv=“refresh”
content=“3;url=http://www.sfsu.edu”>• “3” is number of seconds.• Demo using FrontPage
TABLE Tag
<table border="1" width="100%"> <tr> <td width="25%"></td> <td width="25%"> </td> <td width="25%"> </td> <td width="25%"> </td> </tr> <tr> <td width="25%"> </td> <td width="25%"> </td> <td width="25%"> </td> <td width="25%"> </td> </tr></table>
FORM Tag
• Form attribute:– Action: Specify the URL of a program on a server or an
email address to which a form’s data will be submitted.– Method:
• Get: the form’s data is appended to the URL specified by the Action attribute as a QueryString.
• Post: A preferred method for database processing. Form’s data is sent in the HTTP body.
– Name: Form’s name– Target: Specified a window in which results returned
from the server appear.
QueryString
• A QueryString is a set of name=value pairs appended to a target URL.
• It can be used to pass information from one webpage to another.
• To create a QueryString:– Add a question mark (?) immediately after a URL.– Followed by name=value pairs separated by
ampersands (&).
• Example: • <A Href=“http://my.com/Target.htm?CustID=C1&Cname=Chao”>
Creating a QueryString
• User typed URL
• As part of a URL specified in an anchor tag.
• Via a form sent to the server with the GET method.
SCRIPT Tag
• <SCRIPT LANGUAGE = VBSCRIPT>
• <SCRIPT LANGUAGE = JAVASCRIPT>
• HTML and Vbscript are not case-sensitive; Javascript is case-sensitive, each statement ends in a semicolon (;).
Script Example
</script>
<SCRIPT LANGUAGE=vbscript>
<!--
statements
-->
</SCRIPT>
<body>
<p>Hello World</p>
<script language="javascript1.3">
document.write ("<h1>Hello world</h1>");
</script>
</body>
Variable Declaraton
• JS: var intrate, term, amount;• VB: dim intrate, term, amount• Data Type:
– Variant - a variable’s data type is determined when it is initialized to its first value.
• Variable scope:– Local: Variables declared in a function or procedure.
– Global: Variables declared in the heading section, but not in a function or procedure.
Special Characters in JavaScript
• Escape characters• Special characters:
– Carriage return: \r “Welcome “ & “\r” & cName
– Backslash: \\ “c:\\Inetpub\\wwwroot\\home.htm”
– New line: \n
– Double quotation mark: \”
– Single quotation mark: \’
– Tab space: \t
Special Characters in VBScript
• VB uses CHR function to return special characters.
• CHR(number of ANSI character code)– Carriage return: chr(11)
– Backslash: chr(92)
– New line: chr(10)
– Double quotation: chr(34)
– Single quotation: chr(39)
– Tab: chr(9)
Arrays
• JS: var arrayName = new Array(array size);• var Pet = new Array(2);
• Pet[0]=“dog”;
• Pet[1]=“cat”;
• Pet[2]=“bird”;
• VB: dim arrayName(array size)• Dim Pet(2)
• Pet(0)=“dog”
• Pet(1)=“cat”
• Pet(2)=“bird”
Comments
• JS: – Single-line comment: //– Multiple-line comments: /* … */
• VB: single quotation mark ‘
Operators• Arithmetic operators:
– JS: +, -, *, /, Math.pow(x,y), etc.• Math is an object with many methods such as round(x),
random(), sqrt(x), ceil(x), floor(x), etc.
– JS: Prefix operator: ++VarName, --VarName• Postfix operator: varName++, varName--
– VB:+. -, *, /, ^
• Comparison operators:– JS: = = , !=, <, >, <=, >=– VB: =, <>, <, >, <=, >=
• Logical operators:– JS: &&, ||, !– VB: AND, OR, NOT
IF Then StatementsJS: if (condition) {
statements;
}
else {
statements;
}
VB: if (condition) then
statements
else
statements
end if
Case StatementsJS: Switch Case Statement
switch(varable name) {case value1:
statements;break;
case value2:statements;break;
…default:
statements;break;
}
VB: Select Case statement
Loop StructuresJS: 1. while (condition) {
statements;}
2. do{statements;
} while (condition)
3. for (var I = 0; I<5;I=I+1){statements;
}
JavaScript Build-In Objects and Methods
• Math object• String object: In JS, a string variable is an object
and can be created by:– varName = “Smith”– varName = new String(“Smith”)
• String object methods:– bold, fontcolor, fontsize, toLowerCase, toUpperCase– anchor (create a bookmark), link (create a link)– Substring, split (split a string into an array)
Examples of Using String’s Methods
var test = “Click Here”;
var website = http://www.sfsu.edu;
test.link(website);
var test = “one, two, three”;
var newArray = test.split(“,”);
Note: split is useful in parsing a queryString.
JavaScript’s Conversion Functions
• toString() example:• Price=5;
• Qty=10;
• Amount=Price*Qty;
• Document.write (Amount.toString());
• Eval• strVar = “5”;
• numVar = eval(strVar)
JavaScript Functions
• Defining functions– function functionName(arg1,..,argN){
• Statements;• return return value;
– }
Note: 1. The arguments are optional.2. The return statement is optional. A function is not
required to return a value.
VBScript Functions
• Defining functions:– Function functionName(arg1,..,argN)
• Statements
• functionName=returnValue
– End Function
– Note: Unlike VB, a function is not required to return a value.
Document Object Model
N avig a to r L oca tion
Text
R ad io
C h eckB ox, e tc
F orm co llec tion
Im ag e
L in k
A n ch or, e tc
O th er co llec tion s
D ocu m en t H is to ry F ram e
W in d ow
Window Object
• The Window object represents a Web browser window.
• We use the properties and methods of a Window object to control browser window.
Window Object• Properties:
– window.status, window.defaultstatus– window.document, window.history, window.location.– Window.name
• Methods:– window.open (“url”, “name”, Options)
• Options: menubar=no, status=no, toolbar=no, etc.
– window.close– window.alert(“string”)– window.prompt(“string”)– Window.confirm()– window.prompt(“string”, “default string”)– window.focus() , window.blur() :set/remove focus– Window.setTimeout(“statements”, milliseconds)
Document Object
• The document object represents the actual web page within the window.
• Properties: – background, bgColor, fgColor, title, url, lastModified,
domain, referrer, cookie, linkColor, etc. • Ex. document.bgColor=“silver”;
• Methods: – Document.write (“string”)– Document.open, close
• Demo (docProp.htm, testDoc.htm)
Navigator Object
• The navigator object provides information about the browser.
• Properties:– Navigator.appName:browser name– Navigator.appCodeName: browser code name– Navigator.appVersion– Navigator.platform: the operating system in
use.
Location Object
• Allows you to change to a new web page from within a script code.
• Properties:– Host, hostname, pathname– Href: full URL address– Search: A URL’s queryString
• Methods:– location.reload()– location.replace(); replace current page and old page’s entry
in the history.
• To open a page: location.href = “URL”
History Object
• Maintain a history list of all the documents that have been opened during current session.
• Methods:– history.back()– history.forward()– history.go(): ex. History.go(-2)
HTML Tags and Events
• Link <a> </a>: click, mouseOver, mouseOut• Image <img>: abort(loading is interrupted), error,
load.• Area <area>: mouseOver, mouseOut• Body <body>: blur, error, focus, load, unload• Frameset: blur, error, focus, load, unload• Frame: blur, focus• Form: submit, reset• Textbox, Text area: blur, focus, change, select• Button, Radio button, check box: click• List: blur, focus, change
Event Handler
• Event handler name: on + event name– Ex. onClick
• Three ways of writing handler:– 1. Within the tag
• <input type = “button” name =“ button1” value “click here” onCLick = window.alert(“you click me”)>
– 2. Event function: onCLick=“clickHandler()”
– 3. Event procedure as in VB.• Sub button1_onCLick()
Form Object• Form Input/Select object:
– Textbox, radio button, check box, drop-down list box, text area, push button, submit button, reset button.
• Event-Handler:– onBlur (lose focus), onCHange, onClick, onFocus,
onKeyDown, onKeyPress, onKeyUp, onLoad (when a document is loaded), onMouseDown, onMouseMove, onMouseOut, onMouseOver, onMouseUp, onReset(when click the reset button), onResize(when window is resized), onSubmit.
• Refer an input object in a form:– document.formname.inputobjName.Value
• Demo: showFormData.htm
Forms Collection
• The forms collection is a collection of form objects within the document object.
• To retrieve a form’s`property:– document.form[index].property
• Base 0 index
– Document. formname.property
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