2. XHTML Basics
• XHTML stands for EXtensible HyperText Markup Language
• XHTML is a stricter, more XML-based version of HTML
• XHTML is HTML defined as an XML application
• XHTML is supported by all major browsers
3. XHTML for the Experts
• XML is a markup language where all documents must be marked up
correctly (be "well-formed").
• XHTML was developed to make HTML more extensible and flexible to
work with other data formats (such as XML). In addition, browsers ignore
errors in HTML pages, and try to display the website even if it has some
errors in the markup. So XHTML comes with a much stricter error handling.
4. Strict?
• <!DOCTYPE> is mandatory
• The xmlns attribute in <html> is mandatory
• <html>, <head>, <title>, and <body> are mandatory
• Elements must always be properly nested
• Elements must always be closed
• Elements must always be in lowercase
• Attribute names must always be in lowercase
• Attribute values must always be quoted
• Attribute minimization is forbidden
5. Example XHTML code
• <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
• "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
• <html xmlns="http://www.w3.org/1999/xhtml">
• <head>
• <title>Title of document</title>
• </head>
• <body>
• some content here...
• </body>
• </html>
6. Compared to HTML code
• <html>
• <head>
• </head>
• <body>
• </body>
• </html>
7. Importance of XHTML
• XHTML documents are XML conforming as they are readily viewed, edited, and
validated with standard XML tools.
• XHTML documents can be written to operate better than they did before in
existing browsers as well as in new browsers.
• XHTML documents can utilize applications such as scripts and applets that rely
upon either the HTML Document Object Model or the XML Document Object
Model.
• XHTML gives you a more consistent, well-structured format so that your webpages
can be easily parsed and processed by present and future web browsers.
8. Importance of XHMTL
• You can easily maintain, edit, convert and format your document in the long run.
• Since XHTML is an official standard of the W3C, your website becomes more
compatible with many browsers and it is rendered more accurately.
• XHTML combines strength of HTML and XML. Also, XHTML pages can be
rendered by all XML enabled browsers.
• XHTML defines quality standard for your webpages and if you follow that, then
your web pages are counted as quality web pages. The W3C certifies those pages
with their quality stamp.
9. XML Basics
• Stands for eXtensible Markup Language
• Used to define customized markup languages
• We are already familiar with XML since we understand HTML
10. Interesting XML Notes
• XML is a software- and hardware-independent tool for storing and transporting
data.
• XML was designed to store and transport data
• XML was designed to be self-descriptive
• Maybe it is a little hard to understand, but XML does not DO anything.
11. XML Just Stores Data
• XML is just information wrapped in tags.
• XML is the parent language to HTML
• XML is used to contain data, not to display data
• XML tags are custom, defined by the author.
• HTML can enrich XML data but neither can replace the other. One is used
for storing (XML) and the other is used for displaying (HTML).
12. XML Rules
• XML elements must follow these rules:
• Can contain letters, numbers and other characters
• Can’t start with a number or punctuation character
• Can’t start with ‘xml’
• Can’t contain spaces
13. Writing in XML
• XML attributes must be quoted as in: <employee type=‘permanent’>
• Alternatively, you can write
• <employee>
<type>permanent</type>
</employee>
• Both above examples accomplish the same goal and there are no rules as to which
one is right. The second example is easier to read and looks nicer.
14. XML vs. HTML
• XML was designed to carry data - with focus on what data is
• HTML was designed to display data - with focus on how data looks
• XML tags are not predefined like HTML tags are
15. You Define XML Tags
• The XML language has no predefined tags.
• Tags are "invented" by the author of the XML document.
• HTML works with predefined tags like <p>, <h1>, <table>, etc.
• With XML, the author must define both the tags and the document structure.
16. Why Use XML?
• It simplifies data sharing
• It simplifies data transport
• It simplifies platform changes
• It simplifies data availability
17. More Reasons to use XML
• XML stores data in plain text format. This provides a software- and hardware-
independent way of storing, transporting, and sharing data.
• XML also makes it easier to expand or upgrade to new operating systems, new
applications, or new browsers, without losing data.
• With XML, data can be available to all kinds of "reading machines" like people,
computers, voice machines, news feeds, etc.
18. In What Ways Can We Use XML?
• Create a list of books
• Create a list of transactions
• Create a news article header
• Detail weather service information
• And much, much more!
19. XML Example Code
• <?xml version="1.0" encoding="UTF-8"?> Prolog
• <note> Root
• <to>Tove</to>
• <from>Jani</from>
• <heading>Reminder</heading>
• <body>Don't forget me this weekend!</body>
• </note> notice all have closing tags like HTML!!!!
20. XML can use HTML tags
• Tags you have previously seen can be used in XML, such as:
• <b></b> for bold text
• <i></i> for italicized text
21. Attributes Must Be Quoted
• <note date="12/18/1953">
• <to>Tove</to>
• <from>Jani</from>
• </note>
• In this example our attribute is our date 12/18/1953
22. Entity References
< < less than
> > greater than
& & ampersand
' ' apostrophe
" " quotation mark
Entity references help you to avoid errors
23. Comments in XML
• <!-- This is a comment -->
• This exact structure is required for XML comments
24. XML Elements
• An element can contain:
• Text
• Attributes
• other elements
• or a mix of the above
• Examples could be <rate>19.99</rate>
25. XML Naming Rules Reminder
• XML elements must follow these naming rules:
• Element names are case-sensitive
• Element names must start with a letter or underscore
• Element names cannot start with the letters xml (or XML, or Xml, etc)
• Element names can contain letters, digits, hyphens, underscores, and periods
• Element names cannot contain spaces
• Any name can be used, no words are reserved (except xml).
26. Standards Advising Naming Rules
• Create descriptive names, like this: <person>, <firstname>, <lastname>.
• Create short and simple names, like this: <book_title> not like this: <the_title_of_the_book>.
• Avoid "-". If you name something "first-name", some software may think you want to subtract "name" from "first".
• Avoid ".". If you name something "first.name", some software may think that "name" is a property of the object "first".
• Avoid ":". Colons are reserved for namespaces (more later).
• Non-English letters like éòá are perfectly legal in XML, but watch out for problems if your software doesn't support them.
29. XSLT
• XSLT - eXtensbile Stylesheet Language Transformations
• XSLT transform XML into HTML, before it is displayed by a browser
• You can transform a XML document into an HTML document just by
linking the XML document to the XSLT file by using the following line:
• <?xml-stylesheet type="text/xsl" href="xsltexample.xsl"?>
30. Another XML Example
• <xml>
<addressbook>
<address>
<name>Mark Nazzaro</name>
<email>nazzarma@shu.edu</email>
</address>
<address>
<name>David Rosenthal</name>
<email>rosentdv@shu.edu</email>
</address>
</addressbook>
</xml>
31. JSON Basics
• JSON stands for JavaScript Object Notation
• JSON is easier to parse than XML
• Properties make up a JSON object
• JSON.parse() parses retrieved data
• JSON.stringify() converts a JavaScript object into a string
32. JSON vs. XML
• Syntax for storing and exchanging
data
• Similar to XML:
• Hierarchical – values embedded
within values
• Human readable
• Both can use XMLHttpRequest
• Different from XML:
• No tags
• Shorter
• Quicker to read and write
• JSON uses arrays
• Easier to parse JSON
33. JSON Object Example
• A car is an object which has three properties describing it
• Make – String value representing the make of the car
• Model – String value representing the model of the car
• Price – Numeric value representing the price of the car
34. How That Looks in XML
<car>
<make>Chevrolet</make>
<model>Suburban</model>
<price>60000</price>
</car>
35. How It Looks in JSON
{
"make": "Chevrolet",
"model": "Suburban",
"price": 60000
}
37. Accessing Values in Objects
• In order to access the values of an object, you can
use the dot (.) notation
myObj =
{“firstName”:”Matt”,”lastName”:”Marino”,”
age”:34};
firstName = myObj.firstName;
lastName = myObj.lastName;
age = myObj.age;
• You can also access the values using a bracket
notation
firstName = myObj[“firstName”];
lastName = myObj[“lastName”];
age = myObj[“age”];
• You can also access all of the values using a for
loop:
for (x in myObj)
{
}
38. Parsing
• When data is received from a web server, it can be parsed with JSON.parse() and it
becomes a JavaScript object.
var text = '{ "name":"John", "birth":"1986-12-14", "city":"New York"}';
var obj = JSON.parse(text);
obj.birth = new Date(obj.birth);
document.getElementById("demo").innerHTML = obj.name + ", " + obj.birth;
39. Stringify
• Convert a JavaScript object into a string
var obj = { "name":"John", "age":30, "city":"New York"};
var myJSON = JSON.stringify(obj);
document.getElementById("demo").innerHTML = myJSON
45. In Class Example
Create a booklist file in both XML and JSON (meaning two different files - one called books.xml and one
called books.json). Include in your data storage files the following book info: title of book, author of
book, and price of book.
46. In Class Example Help
• XML – refer back to slide 34
• JSON – refer back to slide 35
