Transcript chapter1
The Web Wizard’s Guide to HTML Chapter One World Wide Web Basics Chapter Objectives Show how Web page authors and computers work together Look behind the scenes when a browser displays a Web page Explain what HTML is and how Web pages use HTML Demonstrate how to create Web pages with nothing more than a text editor and a browser Explore the role of HTML standards on the Web To View the World Wide Web You Need An Internet-ready computer An Internet access account A Web browser To Create a Web Site You Need An Internet-ready computer A text editor (or Web page construction kit) An Internet access account A password-protected account on a Web server Uniform Resource Locator (URL) All Web pages are addressed with URLs The URL specifies – A server name – A directory path – A filename URLs are part of the HTTP (Hypertext Transfer Protocol) communications protocol. Web Page Displays All browsers are designed to display HTML files as well as some other presentation languages (e.g. XML, etc.) Browsers have to rework their page displays whenever a browser window is resized Web pages can look a lot different on different computers or different browsers Web page authors cannot completely control their page displays (unlike desktop publishing or word processing software) The Hypertext Markup Language (HTML) HTML formatting commands control Web page displays All HTML formatting is achieved with HTML elements All HTML elements are based on HTML tags and tag-pairs HTML files can be created with text editors An HTML TagTemplate <html> <head> <title> (insert text for the browser’s title bar here) </title> </head> <body> (insert visible Web page elements here) </body> </html> HTML Editors Pros – Offer lots of useful features – Help you avoid tagging errors – Can save time Cons – Can interfere with HTML mastery – Can be intimidating for beginners The Web Page Development Cycle 1. 2. 3. 4. 5. Edit your HTML file Save your HTML file Load the file into your Web browser Review the file with your Web browser Revise your HTML file with a text editor Repeat this cycle as often as needed (SAVE FREQUENTLY) Industry Standards Most HTML tags are in the official HTML standard All HTML-compliant browsers recognize the standard HTML tag set – – – Some browsers may display HTML tags differently from other browsers Some browsers may add support for tags not approved by the W3C Some browsers may add or change the attributes available for HTML tags The World Wide Web Consortium (W3C) sets the industry standard for HTML Document Type Definition You can tell the web browser or editor which version of HTML you are using by inserting the DOCTYPE SGML tag at the beginning of your document. This tag specifies what type of document you are wanting the browser to render, the version of code you have written the document in, and the character set that should be used to display the document. <!DOCTYPE HTML PUBLIC “-//W3C/TDT HTML 4.01//EN”> Non-Standard HTML Some HTML tags are browser-specific extensions to HTML Netscape Navigator and Internet Explorer do not always recognize each other’s HTML extensions Web pages that use non-standard HTML may not display well for all users Browser manufacturers create their own HTML extensions to influence the industry standard HTML Validation Services A validation service on the Web can check an HTML file for you A validation service can be used to identify tagging errors and HTML extensions Some HTML tagging errors are difficult to locate by manual inspection If you don’t use an HTML editor, a validation service can be very helpful