View
216
Download
0
Tags:
Embed Size (px)
Citation preview
Assumptions
• You have had no formal training in web programming
• But it is assumed that you have picked up a lot of relevant material already
• Nevertheless, the course will review basic notions, to ensure a “level playing field”
Servers and Browsers
• Servers make web documents, which are specified in HTML, available on request to browsers
• Browsers display, to users, web documents which have been received from servers
Web Programming
• Programming for the World Wide Web involves both– server-side programming, and– client-side (browser-side) programming
Client-side programming
• In this module, we will consider the following mechanisms for client-side programming:– HTML 4.0– Cascading Style Sheets– Javascript– Java applets
Server-side Programming
• In this module, we will consider – the Hyper Text Transfer Protocol (HTTP)– the Common Gateway Interface (CGI) protocol
for sending information between servers and appln programs running on the same machines
– server-side programming in Perl, PHP and Java
Assessment
• Of the marks available for the module,– 70% are available from the end-of-year written
examination– 30% are available from continuous assessment,
a series of in-class tests that will be administered from time to time
Assumption
• It is assumed that you have already used HTML quite a bit, even though you have had no formal course in it
• Beware that good HTML programming methodology is still evolving
• This course will adhere rigidly to the latest standards for coding in HTML 4.0, even though browsers tend to be more tolerant
• HTML is the language used for specifying WWW documents
• A specification, in HTML, of a WWW document contains raw content (text, video, etc.) along with items called tags which are used to tell browsers about the content
HTML Specification of a Simple Document
<HTML> <HEAD> <TITLE> Hello Document </TITLE> </HEAD> <BODY> Hello there </BODY> </HTML>
• The HTML fragment <TITLE> Hello Document </TITLE> tells the browser what title to place on the top line
of the browser display
• The HTML fragment <BODY> Hello there </BODY> tells the browser what to put in its content display region
Browsers treat documents slightly differently
• See how the document titles are placed differently on the top line of the browser
• See how the content display regions have different colours
Testing your web-site
• When you make you web-site live, it may be accessed by anybody on the WWW
• You have no idea which browser they will be using
• But it is a good idea to test you site on the most likely browsers
A tag pair contains something:
• The tag pair <HTML> … </HTML> contains a HTML specification of a document, including always– “header” information, that is info about the
document– the content of the document
• The tag pair <HEAD> … </HEAD> contains the header information about the document, including– the title of the document (always present)– other information (optional)
• the tag pair <TITLE> … </TTLE> contains the title of the document
Thus, the simplest HTML specification is of the form:
<HTML>
<HEAD>
<TITLE> Some-title </TITLE>
</HEAD>
<BODY> Some-content </BODY>
</HTML>
Example document spec:
<HTML>
<HEAD>
<TITLE> A silly document </TITLE>
</HEAD>
<BODY> Isn’t this easy???? </BODY>
</HTML>
Another example specification:
<HTML>
<HEAD>
<TITLE> Silly document #2 </TITLE>
</HEAD>
<BODY> Well, well!! </BODY>
</HTML>
Dividing text into paragraphs<HTML>
<HEAD> <TITLE> The Ironies of History </TITLE> </HEAD>
<BODY>
<P>In August 1914, a bullet was fired in Sarajevo which led,
indirectly, to the deaths of thousands of Congolese in 1999.
The bullet in Sarajevo caused World War I which, in turn, caused
the Russian Revolution. </P>
<P>The Russian Revolution led, eventually, to the Cold War. The Cold
War caused The West to support Mobutu in his kleptocratic rule of
the Congo, leading to such a breakdown of society that the Congo
has experienced a series of civil wars in the late 1990s. </P>
</BODY>
</HTML>
The Paragraph tags:
• The tag <P> is used to start a paragraph while the tag </P> is used to end a paragraph
• Ensure you use the </P> tag at the end of a paragraph:– some browsers do not insist on it but other
programs rely on its presence
• NEVER use a </P> tag to get “white space”