Kevin Murphy Basics of XML Masters Project CS 490

Kevin Murphy What is XML eXtensible Markup Language n Describes the structure of a document n Based on SGML ( Standard Generalized Markup Language ) n XML is focused on Content description n Make your own elements n Each element has a name and is contained in a tag. n Portable, structured dynamic and descriptive

Kevin Murphy What XML Isn’t n Static n A set of pre defined tags n Purpose of XML is to describe the general structure relating to the content inside a document—NOT that content’s actual appearance on the page or on the screen.

Kevin Murphy Rules About Tags n Tags have a beginning and an ending tag, surrounding the text that they affect. n Closing tags have the tag name preceded by a slash (/). n All XML tags have a beginning and an end. n All XML tags are case insensitive. n Caution: If you forget to close a paired set of tags or you include a backslash or some other character rather than a forward slash, the tag won’t be closed, and the command will stay in effect.

Kevin Murphy Tag naming conventions n In XML, tags can be invented that best describe the contents. n using markup that is readable by both humans and machines. n XML tags look something like this: Chevy

Kevin Murphy The Tag n This tag indicates that the content of this file is in XML language. n All the text and other XML tags and commands should be placed within beginning and ending XML tags. n Example: n...Web page...

Kevin Murphy XML Formatting XML has to be well formed, This means the file must follow three basic rules: 1. The document starts with an XML declaration,. 2. There is a root element in which all others are contained. 3. All elements must be properly nested. No overlapping is permitted.

Kevin Murphy Step 1: Creating an XML Page n What is minimally needed: A. a basic text editor (to create your XML files) B.a browser to view them. IE 5 has an internal XML viewer and debugger. n File extension: Give the filename an extension of.xml n Example: file.xml n A good rule is to use lowercase names n Don’t use spaces or special characters—(Just letters and numbers are fine.)

Kevin Murphy Step 2: Viewing XML Source Pages n You see the tags in your browser; as part of the final result. n Most Web browsers will allow you to view the XML source code. n In IE, go to the view menu and choose source.

Kevin Murphy Step 3: View the Document n Start up your Web browser n From the menu bar, select File, Open Page (or a similar command depending on the browser).

Kevin Murphy Step 4: If your page didn’t work! n Check your code n Look for opening and closing tags n If the text repeated in the browser, make sure the file was saved with the.xml extension. n After making corrections, save the file, and try viewing it again.

Kevin Murphy Example Kevin Murphy cs neiu

Kevin Murphy Future of XML n This is a new language which Microsoft is still expanding. It is dynamic so there are many directions it can go, as with web the future is open.