Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 11
Transcript
Chapter 11 Creating Framed Layouts Principles of Web Design, 4th Edition Objectives • Understand the benefits and drawbacks of frames • Understand and use frame syntax • Customize frame characteristics including scroll bars, borders, and margins • Understand and use frame targeting and special targeting names • Design content to fit framesets properly • Design framesets that accommodate different screen resolutions Principles of Web Design, 4th Edition 11-2 Understanding Frames Principles of Web Design, 4th Edition 11-3 Understanding Frames • Frames allow you to divide the browser window into independent windows, each displaying a separate HTML document Principles of Web Design, 4th Edition 11-4 Principles of Web Design, 4th Edition 11-5 Frame Benefits • Frames allow users to scroll independently in one frame without affecting the contents of an adjoining frame • Frames are an ideal way to present large collections of information that are hard to navigate using traditional single-page browser display Principles of Web Design, 4th Edition 11-6 Principles of Web Design, 4th Edition 11-7 Frame Drawbacks • • • • Inaccurate bookmarking Download overhead Visual and navigation confusion Poor indexing with search engines Principles of Web Design, 4th Edition 11-8 Frame Syntax Principles of Web Design, 4th Edition 11-9 The <frameset> Element • The <frameset> element is the container for the frameset code • The cols and rows attributes let you specify the characteristics of the frameset • You can specify a frameset as either cols or rows, but not both Principles of Web Design, 4th Edition 11-10 The <frame> Element • The <frame> element is an empty element • The src attribute provides the location of the file that is displayed within the frame Principles of Web Design, 4th Edition 11-11 Rows Frameset Syntax • Two-row frameset: <frameset rows=”50%,50%”> <frame src=”top.htm”> <frame src=”bottom.htm”> </frameset> Principles of Web Design, 4th Edition 11-12 Principles of Web Design, 4th Edition 11-13 Columns Frameset Syntax • Two-column frameset: <frameset cols=”150,*”> <frame src=”left.htm”> <frame src=”right.htm”> </frameset> Principles of Web Design, 4th Edition 11-14 Principles of Web Design, 4th Edition 11-15 The <noframes> Tag • The <noframes> tag lets you provide an alternate page for users who do not have a frames-compliant browser • You can enclose the contents of a standard Web page, contained in a set of <body> tags, within the <noframes> element Principles of Web Design, 4th Edition 11-16 Nesting Frames • Nesting allows you to break the screen into both row and column frames Principles of Web Design, 4th Edition 11-17 Nested Frameset Syntax • Nested frameset: <frameset rows="40,*"> <frame src="topnav.htm"> <frameset cols="20%,80%"> <frame src="left.htm"> <frame src="right.htm"> </frameset> </frameset> Principles of Web Design, 4th Edition 11-18 Principles of Web Design, 4th Edition 11-19 Restricting Resizing • By default, the user has the option of resizing your frames by clicking and dragging the frame border • In most situations you probably want to restrict resizing, so that the user sees the frameset the way you intended • To restrict resizing, add the noresize attribute to the <src> elements in your frameset Principles of Web Design, 4th Edition 11-20 Principles of Web Design, 4th Edition 11-21 Customizing Frame Characteristics Principles of Web Design, 4th Edition 11-22 Controlling Scroll Bars • By default, scroll bars in frames are set to appear automatically when needed if the content is not accessible within the frame window • Remove the scroll bar by adding the scrolling=“no” attribute to the <src> element Principles of Web Design, 4th Edition 11-23 Principles of Web Design, 4th Edition 11-24 Principles of Web Design, 4th Edition 11-25 Controlling Frame Borders • As with tables, you can choose not to display frame borders, or to remove the default border spacing between frames entirely • This technique lets you create seamless frames with no visible dividing line (unless a scroll bar pops up) • To remove frame borders, add border=“0” to the <frameset> tag Principles of Web Design, 4th Edition 11-26 Principles of Web Design, 4th Edition 11-27 Controlling Frame Margins • Two frame attributes let you control the pixel width of both the vertical and horizontal margins in a frame • marginwidth lets you control the left and right margin, while marginheight affects the top and bottom margins • Setting these attributes to 0 lets you remove the margins entirely, allowing your content to touch the sides of the frame Principles of Web Design, 4th Edition 11-28 Principles of Web Design, 4th Edition 11-29 Targeting in Framesets Principles of Web Design, 4th Edition 11-30 Frame Targeting • By default, a link loads into the same frame from which it was selected • You can change this default behavior and target the destination of a link to another frame in the frameset Principles of Web Design, 4th Edition 11-31 Principles of Web Design, 4th Edition 11-32 Frame Targeting (continued) • To target from one frame to another, you must perform two tasks: 1. Name your frames using the name attribute in the frame element 2. Target links to display their content in the named frame Principles of Web Design, 4th Edition 11-33 Naming Frames • To name a frame, add the name attribute to the <frame> element • You do not have to name all of the frames within a frameset, only the frames you want to target <frame src="article1.htm" name=“main"> Principles of Web Design, 4th Edition 11-34 Targeting Named Frames • To target the named frame, you must edit the HTML document that contains the <a> elements and provide target attributes that tell the browser which frame displays the content • You can use the target attribute in either the <base> or <a> elements Principles of Web Design, 4th Edition 11-35 Targeting Named Frames (continued) • Adding the <base> element lets you set the default target frame for all of the links in the document <base target="main"> • You can override a default base target by using the target attribute in the <a> element <a href="article1.htm" target=”frame2”>article 1</a> Principles of Web Design, 4th Edition 11-36 Using Special Target Names • There are four special target names that you can use with the target attribute in either the <base> or <a> elements • Notice that all of these special names begin with an underscore – Any other target name that begins with an underscore will be ignored by the browser Principles of Web Design, 4th Edition 11-37 Principles of Web Design, 4th Edition 11-38 Principles of Web Design, 4th Edition 11-39 Using _blank • The _blank special target name lets you load the linked content into a new instance of the browser • Notice that the Back button is not available in the new browser window because this is the first page in the new window – Not being able to use Back can be disorienting to users who rely on it for navigation Principles of Web Design, 4th Edition 11-40 Principles of Web Design, 4th Edition 11-41 Using _top • Using _top as a special target name displays the linked content in a non-framed window using the same instance of the browser • The Back button is available if the user wants to return to the previous page – Since the browser maintains only one open window, there is no additional memory overhead or confusion for the user Principles of Web Design, 4th Edition 11-42 Principles of Web Design, 4th Edition 11-43 Designing Effective Frames Principles of Web Design, 4th Edition 11-44 Designing Effective Frames • Build your pages to fit within the frames in which they will display, and accommodate different screen resolutions that can affect the size of the frame within the frameset • Decide whether you will use fixed or relative framesets • You can also choose to mix these two measurement types within a single frameset, which can be the best way to handle multiple screen resolutions Principles of Web Design, 4th Edition 11-45 Mixing Fixed and Variable Frames • The following sample framesets demonstrate mixing a fixed frame and a variable frame to accommodate different screen resolutions Principles of Web Design, 4th Edition 11-46 Principles of Web Design, 4th Edition 11-47 Principles of Web Design, 4th Edition 11-48 Principles of Web Design, 4th Edition 11-49 Summary • Use frames judiciously • Make sure that your content demands or benefits from the use of frames • Build simple framesets with no more than two or three frames • Be aware of the limitations of frames Principles of Web Design, 4th Edition 11-50 Summary (continued) • Frames are not the best choice for the toplevel page of your Web site • Use the <noframes> element to contain alternate information about your Web site Principles of Web Design, 4th Edition 11-51 Summary (continued) • Use the special target names to solve design problems, choosing _top over _blank whenever possible • Build your framesets using a combination of fixed and variable frame widths • Test your work for compatibility across browsers Principles of Web Design, 4th Edition 11-52
