Scripting - Client and Server Sidex

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Transcript Scripting - Client and Server Sidex

Scripting Languages
Client Side and Server Side
Examples of client side/server side
Examples of client-side side include:
• JavaScript
• Jquery (uses a JavaScript library containing very easy to use,
condensed functions and syntax - http://jquery.com/download/ )
• VBScript (simplified version of Visual Basic)
• ActionScript (used in Flash animation/web pages)
Examples of server-side include:
• PHP (.php)
• ASP (.asp)
• JSP (.jsp),
• ASP.NET (.NET) (.aspx),
• COLDFUSION (.cfm)
• RUBY (.rb) RUBY ON RAILS (.rbw)
• PERL (.cgi, .pl, .ipl)
• PYTHON (.py)
Scripting languages require a web
server to run, e.g. Apache and IIS.
Check the server is capable of
running the server-side scripting
language
Advantages/disadvantages of Client Side Scripts
Client side
ADVANTAGES
• Takes load off server (processing done at client end – quicker – uses
less bandwidth)
• Can be used for non essential functions (e.g. navigation, pop ups,
rollovers, form validation, etc.)
• Easy to use – only text editor and a browser required. No testing
software needed
• Makes web pages more interactive
DISADVANTAGES
• Malicious executable code downloaded from a remote server to a web
browser's machine, could be installed and run allowing access to data, to
install a virus, etc.
• Different layout engines (browsers/platforms) may render JavaScript
differently resulting in inconsistency in terms of functionality and
interface.
• The user can turn settings for JavaScript off in their browser
Advantages/disadvantages of Server Side Scripts
Client side
ADVANTAGES
• Can be used for security essential functions (e.g. login screens, form
validation)
• Relatively easy to use – require a server to run and editor to write
scripts
• Script is parsed or interpreted at the server end, and sends the web
page to the web browser as HTML (user cannot see the server script)
• Makes web pages more interactive
• Can access databases and create dynamic web pages
DISADVANTAGES
• Can put more load on server (requires bandwidth, may be sharing server
with other websites, may cause delay in web page being sent to browser)
• Different layout engines (browsers/platforms) may render script
differently resulting in inconsistency in terms of functionality and
interface.
Implementing Client-side Scripts
Client-side JavaScript code can be embedded within HTML documents in a
number of ways:
• Between a pair of script tags <SCRIPT></SCRIPT>
• From an external file specified by the src attribute of a script tag, e.g.
<script TYPE="text/javascript" src="validate.js"></script>
• In an event handler, specified as the value of an HTML attribute such
as onclick, onsubmit or onmouseover, e.g.
<form id="form1" action="validate.js" onSubmit="validateForm()">
• In an URL that uses the special javascript:// protocol
JavaScript Example - Date
<html>
<head> <title>Today's Date</title>
<script language="JavaScript">
function date( )
{
var d = new Date( );
// Create a date object storing today's date and time
document.write(d.toLocaleString( ));
// Write the value of the date object to the document
}
</script>
</head>
<body>
<p>The date and time are <script language="JavaScript">date( ); </script>
</html>
Links
• http://www.jscripters.com/javascript-advantages-and-disadvantages/
• www.w3schools.com
• www.apache.org/