HTML cơ bản - p 21 pdf

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HTML cơ bản - p 21 pdf

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ptg 184 Chapter 4: Using HTML Figure 4.5: The Element Inspector in Google Chrome As shown in Figure 4.5, the Element Inspector has many powerful features, including the graphic display of an element’s box properties. It provides a nicely formatted listing of the HTML source code and the CSS associated with each document element. It is also interactive, changing the displayed proper- ties and values as you mouse over the various page elements. e other tools, accessible from the Element Inspector’s menu bar, oer additional information on the resources used by the page, as well as how the browser loaded them. e Console tool is invaluable for debugging faulty JavaScript functions. I encourage you to become familiar with these tools even if you do not intend to get very deep into Web programming. Other tools are available to help you work with HTML entirely through your browser. Firebug for the Firefox browser is one of my favorites, as is the Web Developer tools collection. Search the Internet for add-ons and exten- sions to your favorite browser with keywords such as “web developer,” and you will nd several that are free and easily installed. From the Library of Wow! eBook ptg Blogging 185 Blogging Blogging has grown tremendously in recent years to become an important channel for people to develop and share content on the Web. Modern blog- ging soware, such as WordPress and Movable Type, go beyond the posting of articles and comments with powerful content-management capabilities. Major media websites are powered by blogging soware. Blogging can be experienced in two ways. If you run your own blog, you have complete control of a website, including its structure, appearance, and operation. As the owner, you have administrator privileges, including the ability to add other users to your blog in various roles. Posting privileges vary according to the user’s role. Administrators, editors, and authors can publish articles on a blog. Contributors can submit articles that are then approved by an editor or administrator for publication. Blogs can also have subscribers. ese are registered users who, depending on the soware, may be allowed to comment on articles and see private posts. A number of blogging services provide almost all the functionality of run- ning your own blog, but without the monthly hosting fees and administrative responsibility of maintaining your own website. ese services include Word- Press.com, Blogger, TypePad, Windows Live Spaces, and others. ey make it easy to publish content on the Web while limiting some of the functional- ity you would have if you owned the website. WordPress.com, for example, does not allow JavaScript and limits the content management functions. And although you can put CSS rules into individual HTML style attributes in a post, you must pay a small yearly fee to be able to edit the global CSS style sheet and give the site your own look. Whether you run your own blog, use one of the blog hosting services, or have posting privileges on someone else’s blog, Web-based blogging soware usually provides a post editor that accepts input in two modes: a visual, what- you-see-is-what-you-get (WYSIWYG) mode and an HTML source edit mode. Figure 4.6 shows the post/page editor in WordPress in the visual editing mode. is editor is called TinyMCE. It is a free, open-source, JavaScript-based editor for HTML from Moxiecode.com. Its extendibility and easy integration into other web soware make it a popular editor for blogs and other content man- agement systems. e two tabs in the upper right of Figure 4.6 labeled Visual and HTML are for switching between the two editing modes. Below those tabs is a double- row toolbar with buttons for creating strong and emphasized text (the B and I From the Library of Wow! eBook ptg 186 Chapter 4: Using HTML buttons), unordered and ordered lists, and block quotes (the “ button). A drop menu labeled “Format” has options to mark up paragraphs, address blocks, preformatted areas, and six levels of headings. ere are buttons for setting text color, inserting images, making links, and entering character entities. In short, TinyMCE can do a lot of HTML, but there is also a lot of HTML that it doesn’t do. It doesn’t let you create tables, insert horizontal rules, or add ele- ment backgrounds, borders, and oating elements other than images. If you need any of those features in a blog post, HTML editing mode is essential. Figure 4.6: The TinyMCE editor in WordPress To create the oating red box shown in Figure 4.6, rst I switched the edi- tor to HTML mode. en I pasted the following HTML code into the editor before the content I previously entered in Visual mode: <div style="float: left; width: 25%; margin-right: 1em; padding: 0.5em; border: solid red; font: large sans-serif; text-align: center;">Error! No Internet Connection!</div> In this situation, you must be careful about extra white space in the content. WordPress assumes that any line breaks are intentional and will inserts break and paragraph elements to preserve the lines as you see them in visual mode. Figure 4.7 shows the same post content using the TinyMCE editor in HTML mode. e line break aer the word “Error!” is intentional in thiscase. From the Library of Wow! eBook ptg Blogging 187 Figure 4.7: The TinyMCE editor in HTML editing mode If you can edit the CSS style sheet for the blog, the division’s style attribute with its CSS rules can be replaced with an id and/or class attribute: <div class="red-box" id="no-internet-error">Error! No Internet Connection!</div> It helps to be specic in creating names for classes and IDs. In the style sheet for the site, the following CSS statements would reproduce the formatting: div.red-box { padding: 0.5em; border: solid red; } #no-internet-error { font: large sans-serif; text-align: center; float: left; width: 25%; margin-right: 1em; } When the HTML is in place, you can switch the editor back to visual mode to continue editing the post, including the text inside the red box. If more extensive editing in HTML is needed, there is an option in each WordPress user’s prole settings to turn o visual editor mode and only accept input into the post editor as is, complete with any HTML markup. I highly recommend doing this when pasting code snippets or widget code that was copied from other web services. Although the TinyMCE editor has no provisions for entering table elements, it does in fact recognize HTML tables, and outlines the table cells and lets you edit the cells’ contents. If you are running your own blog, you can extend TinyMCE’s functionality with plug-ins that add tools for creating tables, hori- zontal rules, and so on. From the Library of Wow! eBook ptg 188 Chapter 4: Using HTML If you nd TinyMCE too limited for your needs, there are other alternatives. Any stand-alone editor that produces HTML markup can be used to compose a post, and the HTML can then be copied and pasted into the blog’s post edi- tor in HTML mode. Final editing can be done in the blog editor’s visual mode. Searching the Web for “HTML editors” or “WYSIWYG Web editors” will provide you with many suggestions on and reviews for such applications. Even though it oers the option to save a document as a web page, Micro- so Word is not a good tool for creating HTML code. A Microso Word document that has been saved in web page format has an awesome amount of extra markup that binds the saved HTML le to Microso Oce’s XML name space. is extra markup ensures that you can move and copy the document contents from Word to PowerPoint to Excel to Outlook and back, keeping most of the typography and layout intact. For those who insist on using Micro- so Word for everything, the TinyMCE editor used in WordPress and other blogging soware has a toolbar button specically for entering content edited in Microso Word. Figure 4.8 shows the paste-from-Word toolbar icon circled. When it is clicked, the input window form appears over the grayed-outpage. 1 Figure 4.8: The Paste-from-Word feature in WordPress’ TinyMCE editor 1. is eect is called exposing, and it is used to give a previously hidden element exclusive focus. A pop- up window, on the other hand, is a new browser window, opened by a script, containing a complete HTML document. From the Library of Wow! eBook ptg Blogging 189 A far better tool for creating Web content is Microso’s Windows Live Writer—a free Windows desktop application that can be downloaded from Microso’s Windows Live support website. Live Writer presents much of the same user interface as TinyMCE but has a better layout and supports editing many of the features that TinyMCE misses. Figure 4.9 shows the editing of a new blog post using Windows Live Writer. e post contains an embedded map from Bing, Microso’s search portal. It was inserted into the post by clicking the link in the right sidebar’s Insert menu. (e arrow is pointing to it.) Figure 4.9: Windows Live Writer post editor To let you see and edit the HTML source code created by Windows Live Writer, a Source tab is provided in the lower-le portion of the editing screen (circled in Figure 4.9). What makes Windows Live Writer a great blog editor is its capability to connect to any blog that supports the Atom Publishing Pro- tocol. is means that Windows Live Writer can import a blog’s CSS settings to provide a Preview mode to see what the formatted page will look like when From the Library of Wow! eBook ptg 190 Chapter 4: Using HTML published. It can also import, edit, and save an existing post or dra. Win- dows Live Writer can even publish directly to a blog, complete with categories, tags, and publication date. ere are several places on a blog where content with limited HTML markup can be entered but no built-in editor is available. is includes post excerpts, comments on posts, and category and other item descriptions. A good example is the practice of coding an excerpt for a post. On some blogs, excerpts can appear in post listings, search result pages, RSS feeds, and email digests. A common practice among bloggers is to code a post excerpt with a thumb- nail version of the post’s principal image. You can do this by hand, of course, but it’s easier to use a post editor’s HTML or Source option. To illustrate this, I used Windows Live Writer to create a blog post about the America’s Cup trophy from the content of Example 2.6 in Chapter 2, “e HTML Language.” Aer saving the entry to my blog as a dra post, I switched to Source mode and made a number of edits appropriate for a blog excerpt. Figure 4.10 shows the excerpt as edited in Windows Live Writer. Figure 4.10: Creating a blog post excerpt using Windows Live Writer From the Library of Wow! eBook ptg Blogging 191 In addition to shortening the text, I made changes to the image element. ese changes from Example 2.6 appear in bold text in the following code snippet: <img style="float: left; padding: 0em 0.5em 0em 0em;" width="75" height="100" alt="The America&#39;s Cup trophy" src="http://AmericasCup2010.com/images/Americas_Cup.jpg"/> Because the excerpt may appear in contexts outside of the blog, I replaced the image element’s class attribute, which referred to a CSS statement in the blog’s style sheet, with explicit CSS rules in a style attribute. e padding between the oating image and the text was reduced because the image will be scaled to a smaller size by the explicit values of the width and height attributes. Finally, a full URL is used to reference the image, again because the excerpt may appear on external websites. All that remains to be done is to copy the code from Windows Live Writer and paste it into the excerpt input box on the blog editing page. Similar blog editors exist for Apple computer users. MarsEdit, for example, shown in Figure 4.11, provides the same features as Windows Live Writer. It is not free but can be purchased for a reasonable price. In contrast to Windows Live Writer, MarsEdit’s editing window is always in HTML mode. A separate preview window (shown under the editing window in the gure) shows how the edited markup will appear in a browser. e preview window operates in real time, reecting changes as they are made in the editing window. A drop-down menu on the right provides easy access to common HTML ele- ments and includes the capability to add your own favorites. As with Windows Live Writer, you can publish directly to a blog from MarsEdit, complete with categories, tags, and other options. From the Library of Wow! eBook ptg 192 Chapter 4: Using HTML Figure 4.11: Editing a blog article using MarsEdit for Apple Macintosh computers Google Docs Google Docs is a collection of oce productivity application services acces- sible “from the cloud.” at is, both the application soware and all created documents exist on Google’s Internet servers and not on each individual user’s personal computer. is allows documents to be accessed and worked on from any browser on any computer connected to the Web. Having the documents in the cloud also allows them to be shared and edited collaboratively. Google Docs provides applications for the creation and editing of four types of documents: word processing documents, spreadsheets, presentations, and input forms. Content in any document type can be copied and placed into other types of documents. Forms are automatically tied to spreadsheets for storage of content entered into form elds. In this respect, an input form is just a dierent view of a spreadsheet. Figure 4.12 shows the management page of Google Docs. Aer logging into a Google account, you go to http://docs.google.com. e management page, also called the Explorer, allows the user to organize documents into folders, create new documents, and share them. On the le side of Figure 4.12, the Create New menu has been clicked to show the options for creating a new document. From the Library of Wow! eBook ptg Google Docs 193 Whereas popular desktop applications such as Microso Oce are focused on creating precisely formatted printed documents, Google Docs’ approach is Web-centric. In fact, Google Docs documents are saved as HTML les and can be published directly to the Web. If the user wants to print a document, it is converted to a PDF le and downloaded to the user’s personal computer for printing locally. Figure 4.12: Google Docs management page Google Docs’ word processing application reects the semantic markup approach of HTML. Its WYSIWYG user interface is quite similar to that of the TinyMCE and Windows Live Writer editors. A Styles menu provides a choice of formatting a paragraph, a block quote, or one of the six HTML heading styles. e Font menu oers the most commonly available Web fonts: Arial, Arial Black, Arial Narrow, Times New Roman, Garamond, Georgia, Tahoma, Trebuchet MS, Verdana, Comic Sans MS, and Courier New. An Insert menu lets you insert links, images, tables, and other HTML document objects. Suppose we want to create a Google Docs document with two columns of block-justied text. It might be an article for a local newsletter we are col- laborating on. We start with a new Google Docs document and select the Edit HTML option from the Edit menu, as shown in Figure 4.13. From the Library of Wow! eBook . services, or have posting privileges on someone else’s blog, Web-based blogging soware usually provides a post editor that accepts input in two modes: a visual, what- you-see-is-what-you-get (WYSIWYG). alternatives. Any stand-alone editor that produces HTML markup can be used to compose a post, and the HTML can then be copied and pasted into the blog’s post edi- tor in HTML mode. Final editing. 4.8 shows the paste-from-Word toolbar icon circled. When it is clicked, the input window form appears over the grayed-outpage. 1 Figure 4.8: The Paste-from-Word feature in WordPress’ TinyMCE

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