A Beginner's Guide to HTML Part II: (a brief reference)
You can't get too far in ASP without an intimate knowledge of HTML, so this tutorial will take a newbie through the ABC's of HTML...one step at a time. It's also a great reference for pros who forget how to use little known tags! By pubs@ncsa.uiuc.edu
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KI-Zusammenfassung: This codebase represents a historical implementation of the logic described in the metadata. Our preservation engine analyzes the structure to provide context for modern developers.
Quellcode
<p><font face="Verdana"><b>URLs</b></font></p> <p><font face="Verdana">The World Wide Web uses Uniform Resource Locators (URLs) to specify the<br> location of files on other servers. A URL includes the type of resource<br> being accessed (e.g., Web, gopher, WAIS), the address of the server, and the<br> location of the file. The syntax is:</font></p> <p><font face="Verdana">scheme://host.domain [:port]/path/ filename</font></p> <p><font face="Verdana">where scheme is one of</font></p> <p><font face="Verdana">file<br> a file on your local system<br> ftp a file on an anonymous FTP server<br> http<br> a file on a World Wide Web server<br> gopher<br> a file on a Gopher server<br> WAIS<br> a file on a WAIS server<br> news<br> a Usenet newsgroup<br> telnet<br> a connection to a Telnet-based service</font></p> <p><font face="Verdana">The port number can generally be omitted. (That means unless someone tells<br> you otherwise, leave it out.)</font></p> <p><font face="Verdana">For example, to include a link to this primer in your document, enter:</font></p> <p><font face="Verdana"> <A HREF="<a href="http://www.ncsa.uiuc.edu/General/Internet/WWW/HTMLPrimer.html">http://www.ncsa.uiuc.edu/General/Internet/WWW/HTMLPrimer.html</a>"><br> NCSA's Beginner's Guide to HTML</A></font></p> <p><font face="Verdana">This entry makes the text NCSA's Beginner's Guide to HTML a hyperlink to<br> this document.</font></p> <p><font face="Verdana">For more information on URLs, refer to:</font></p> <p><font face="Verdana"> * WWW Names and Addresses, URIs, URLs, URNs<br> * A Beginner's Guide to URLs</font></p> <p><font face="Verdana"><b>Links to Specific Sections</b></font></p> <p><font face="Verdana">Anchors can also be used to move a reader to a particular section in a<br> document (either the same or a different document) rather than to the top,<br> which is the default. This type of an anchor is commonly called a named<br> anchor because to create the links, you insert HTML names within the<br> document.</font></p> <p><font face="Verdana">This guide is a good example of using named anchors in one document. The<br> guide is constructed as one document to make printing easier. But as one<br> (long) document, it can be time-consuming to move through when all you<br> really want to know about is one bit of information about HTML. Internal<br> hyperlinks are used to create a "table of contents" at the top of this<br> document. These hyperlinks move you from one location in the document to<br> another location in the same document. (Go to the top of this document and<br> then click on the Links to Specific Sections hyperlink in the table of<br> contents. You will wind up back here.)</font></p> <p><font face="Verdana">You can also link to a specific section in another document. That<br> information is presented first because understanding that helps you<br> understand linking within one document.</font></p> <p><font face="Verdana"><b>Links Between Sections of Different Documents</b></font></p> <p><font face="Verdana">Suppose you want to set a link from document A (documentA.html) to a<br> specific section in another document (MaineStats.html).</font></p> <p><font face="Verdana">Enter the HTML coding for a link to a named anchor:</font></p> <p><font face="Verdana"> documentA.html:</font></p> <p><font face="Verdana"> In addition to the many state parks, Maine is also home to<br> <a href="MaineStats.html#ANP">Acadia National Park</a>.</font></p> <p><font face="Verdana">Think of the characters after the hash (#) mark as a tab within the<br> MaineStats.html file. This tab tells your browser what should be displayed<br> at the top of the window when the link is activated. In other words, the<br> first line in your browser window should be the Acadia National Park<br> heading.</font></p> <p><font face="Verdana">Next, create the named anchor (in this example "ANP") in MaineStats.html:</font></p> <font face="Verdana">tml:</font> <p> </p> <font face="Verdana"> <H2><A NAME="ANP">Acadia National Park</a></H2></font> <p> </p> <p><font face="Verdana">With both of these elements in place, you can bring a reader directly to the<br> Acadia reference in MaineStats.html.</font></p> <p><font face="Verdana">NOTE: You cannot make links to specific sections within a different document<br> unless either you have write permission to the coded source of that document<br> or that document already contains in-document named anchors. For example,<br> you could include named anchors to this primer in a document you are writing<br> because there are named anchors in this guide (use View Source in your<br> browser to see the coding). But if this document did not have named anchors,<br> you could not make a link to a specific section because you cannot edit the<br> original file on NCSA's server.</font></p> <p><font face="Verdana">Links to Specific Sections within the Current Document</font></p> <p><font face="Verdana">The technique is the same except the filename is omitted.</font></p> <p><font face="Verdana">For example, to link to the ANP anchor from within MaineStats, enter:</font></p> <p><font face="Verdana"> ...More information about <A HREF="#ANP">Acadia National Park</a><br> is available elsewhere in this document.</font></p> <font face="Verdana"><br> </font> <p><font face="Verdana">Be sure to include the <A NAME=> tag at the place in your document where you<br> want the link to jump to (<H2><A NAME="ANP">Acadia National Park</a></H2>).</font></p> <p><font face="Verdana">Named anchors are particularly useful when you think readers will print a<br> document in its entirety or when you have a lot of short information you<br> want to place online in one file.</font></p> <p><font face="Verdana"><b>Mailto</b></font></p> <p><font face="Verdana">You can make it easy for a reader to send electronic mail to a specific<br> person or mail alias by including the mailto attribute in a hyperlink. The<br> format is:</font></p> <p><font face="Verdana"><A HREF="<a href="mailto:emailinfo@host">mailto:emailinfo@host</a>">Name</a></font></p> <p><font face="Verdana">For example, enter:</font></p> <p><font face="Verdana"><A HREF="<a href="mailto:pubs@ncsa.uiuc.edu">mailto:pubs@ncsa.uiuc.edu</a>">NCSA Publications Group</a></font></p> <p><font face="Verdana">to create a mail window that is already configured to open a mail window for<br> the NCSA Publications Group alias. (You, of course, will enter another mail<br> address!)</font></p> <p><font face="Verdana"> <b> Inline Images</b></font></p> <p><font face="Verdana">Most Web browsers can display inline images (that is, images next to text)<br> that are in X Bitmap (XBM), GIF, or JPEG format. Other image formats are<br> being incorporated into Web browsers [e.g., the Portable Network Graphic<br> (PNG) format]. Each image takes time to process and slows down the initial<br> display of a document. Carefully select your images and the number of images<br> in a document.</font></p> <p><font face="Verdana">To include an inline image, enter:</font></p> <p><font face="Verdana"> <IMG SRC=ImageName></font></p> <p><font face="Verdana">where ImageName is the URL of the image file.</font></p> <p><font face="Verdana">The syntax for <IMG SRC> URLs is identical to that used in an anchor HREF.<br> If the image file is a GIF file, then the filename part of ImageName must<br> end with .gif. Filenames of X Bitmap images must end with .xbm; JPEG image<br> files must end with .jpg or .jpeg; and Portable Network Graphic files must<br> end with .png.</font></p> <p><font face="Verdana"><b>Image Size Attributes</b></font></p> <p><font face="Verdana">You should include two other attributes on <IMG> tags to tell your browser<br> the size of the images it is downloading with the text. The HEIGHT and WIDTH<br> attributes let your browser set aside the appropriate space (in pixels) for<br> the images as it downloads the rest of the file. (Get the pixel size from<br> your image-processing software, such as Adobe Photoshop.)</font></p> <p><font face="Verdana">For example, to include a self portrait image in a file along with the<br> portrait's dimensions, enter:</font></p> <p><font face="Verdana"> <IMG SRC=SelfPortrait.gif HEIGHT=100 WIDTH=65></font></p> <p><font face="Verdana">NOTE: Some browsers use the HEIGHT and WIDTH attributes to stretch or shrink<br> an image to fit into the allotted space when the image does not exactly<br> match the attribute numbers. Not all browser developers think<br> stretching/shrinking is a good idea. So don't plan on your readers having<br> access to this feature. Check your dimensions and use the correct ones.</font></p> <p><font face="Verdana"><b>Aligning Images</b></font></p> <p><font face="Verdana">You have some flexibility when displaying images. You can have images<br> separated from text and aligned to the left or right or centered. Or you can<br> have an image aligned with text. Try several possibilities to see how your<br> information looks best.</font></p> <p><font face="Verdana"><b>Aligning Text with an Image</b><br> By default the bottom of an image is aligned with the following text, as<br> shown in this paragraph. You can align images to the top or center of a<br> paragraph using the ALIGN= attributes TOP and CENTER.</font></p> <p><font face="Verdana"> This text is aligned with the top of the image (<IMG SRC =<br> "BarHotlist.gif" ALIGN=TOP>). Notice how the browser aligns only one line<br> and then jumps to the bottom of the image for the rest of the text.</font></p> <p><font face="Verdana"> And this text is centered on the image (<IMG SRC = "BarHotlist.gif"<br> ALIGN=CENTER>). Again, only one line of text is centered; the rest is below<br> the image.</font></p> <p><font face="Verdana"><b>Images without Text</b><br> To display an image without any associated text (e.g., your organization's<br> logo), make it a separate paragraph. Use the paragraph ALIGN= attribute to<br> center the image or adjust it to the right side of the window as shown<br> below:</font></p> <p><font face="Verdana"><p ALIGN=CENTER><br> <IMG SRC = "BarHotlist.gif"><br> </p></font></p> <p><font face="Verdana">which results in:</font></p> <p> <p><font face="Verdana">The image is centered; this paragraph starts below it and left justified.</font></p> <p><font face="Verdana"><b>Alternate Text for Images</b></font></p> <p><font face="Verdana">Some World Wide Web browsers--primarily those that run on VT100<br> terminals--cannot display images. Some users turn off image loading even if<br> their software can display images (especially if they are using a modem or<br> have a slow connection). HTML provides a mechanism to tell readers what they<br> are missing on your pages.</font></p> <p><font face="Verdana">The ALT attribute lets you specify text to be displayed instead of an image.<br> For example:</font></p> <p><font face="Verdana"> <IMG SRC="UpArrow.gif" ALT="Up"></font></p> <p><font face="Verdana">where UpArrow.gif is the picture of an upward pointing arrow. With<br> graphics-capable viewers that have image-loading turned on, you see the up<br> arrow graphic. With a VT100 browser or if image-loading is turned off, the<br> word Up is shown in your window.</font></p> <p><font face="Verdana">You should try to include alternate text for each image you use in your<br> document, which is a courtesy for your readers.</font></p> <p><font face="Verdana"><b>Background Graphics</b></font></p> <p><font face="Verdana">Newer versions of Web browsers can load an image and use it as a background<br> when displaying a page. Some people like background images and some don't.<br> In general, if you want to include a background, make sure your text can be<br> read easily when displayed on top of the image.</font></p> <p><font face="Verdana">Background images can be a texture (linen finished paper, for example) or an<br> image of an object (a logo possibly). You create the background image as you<br> do any image.</font></p> <p><font face="Verdana">However you only have to create a small piece of the image. Using a feature<br> called tiling, a browser takes the image and repeats it across and down to<br> fill your browser window. In sum you generate one image, and the browser<br> replicates it enough times to fill your window. This action is automatic<br> when you use the background tag shown below.</font></p> <p><font face="Verdana">The tag to include a background image is included in the <BODY> statement as<br> an attribute:</font></p> <p><font face="Verdana"><BODY BACKGROUND="filename.gif"></font></p> <p><font face="Verdana"><b>Background Color</b></font></p> <p><font face="Verdana">By default browsers display text in black on a gray background. However, you<br> can change both elements if you want. Some HTML authors select a background<br> color and coordinate it with a change in the color of the text.</font></p> <p><font face="Verdana">Always preview changes like this to make sure your pages are readable. (For<br> example, many people find red text on a black background difficult to read!)</font></p> <p><font face="Verdana">You change the color of text, links, visited links, and active links using<br> attributes of the <BODY> tag. For example, enter:</font></p> <p><font face="Verdana"><BODY BGCOLOR="#000000" TEXT="#FFFFFF" LINK="#9690CC"></font></p> <p><font face="Verdana">This creates a window with a black background (BGCOLOR), white text (TEXT),<br> and silvery hyperlinks (LINK).</font></p> <p><font face="Verdana">The six-digit number and letter combinations represent colors by giving<br> their RGB (red, green, blue) value. The six digits are actually three<br> two-digit numbers in sequence, representing the amount of red, green, or<br> blue as a hexadecimal value in the range 00-FF. For example, 000000 is black<br> (no color at all), FF0000 is bright red, and FFFFFF is white (fully<br> saturated with all three colors). These number and letter combinations are<br> cryptic. Fortunately an online resource is available to help you track down<br> the combinations that map to specific colors:</font></p> <p><font face="Verdana"> * ColorPro Web server</font></p> <p><font face="Verdana"><b>External Images, Sounds, and Animations</b></font></p> <p><font face="Verdana">You may want to have an image open as a separate document when a user<br> activates a link on either a word or a smaller, inline version of the image<br> included in your document. This is called an external image, and it is<br> useful if you do not wish to slow down the loading of the main document with<br> large inline images.</font></p> <p><font face="Verdana">To include a reference to an external image, enter:</font></p> <p><font face="Verdana"> <A HREF="MyImage.gif">link anchor</A></font></p> <p><font face="Verdana">You can also use a smaller image as a link to a larger image. Enter:</font></p> <p><font face="Verdana"> <A HREF="LargerImage.gif"><IMG SRC="SmallImage.gif"></A></font></p> <p><font face="Verdana">The reader sees the SmallImage.gif image and clicks on it to open the<br> LargerImage.gif file.</font></p> <p><font face="Verdana">Use the same syntax for links to external animations and sounds. The only<br> difference is the file extension of the linked file. For example,</font></p> <p><font face="Verdana"><A HREF="AdamsRib.mov">link anchor</A></font></p> <p><font face="Verdana">specifies a link to a QuickTime movie. Some common file types and their<br> extensions are:</font></p> <p><font face="Verdana">File Type Extension<br> plain text .txt<br> HTML document .html<br> GIF image .gif<br> TIFF image .tiff<br> X Bitmap image .xbm<br> JPEG image .jpg or .jpeg<br> PostScript file .ps<br> AIFF sound file .aiff<br> AU sound file .au<br> WAV sound file .wav<br> QuickTime movie .mov<br> MPEG movie .mpeg or .mpg</font></p> <p><font face="Verdana">Keep in mind your intended audience and their access to software. Most UNIX<br> workstations, for instance, cannot view QuickTime movies.</font></p> <p><font face="Verdana"> <b>Tables</b></font></p> <p><font face="Verdana">Before HTML tags for tables were finalized, authors had to carefully format<br> their tabular information within <PRE> tags, counting spaces and previewing<br> their output. Tables are very useful for presentation of tabular information<br> as well as a boon to creative HTML authors who use the table tags to present<br> their regular Web pages. (Check out the NCSA Relativity Group's pages for an<br> excellent, award-winning example.)</font></p> <p><font face="Verdana">Think of your tabular information in light of the coding explained below. A<br> table has heads where you explain what the columns/rows include, rows for<br> information, cells for each item. In the following table, the first column<br> contains the header information, each row explains an HTML table tag, and<br> each cell contains a paired tag or an explanation of the tag's function.<br> <b>Table Elements</b></font></p> <p><font face="Verdana"> Element Description<br> <TABLE> ... defines a table in HTML. If the BORDER attribute is<br> </TABLE> present, your browser displays the table with a border.<br> <CAPTION> ... defines the caption for the title of the table. The default<br> </CAPTION> position of the title is centered at the top of the table.<br> The attribute ALIGN=BOTTOM can be used to position the<br> caption below the table.<br> NOTE: Any kind of markup tag can be used in the caption.<br> <TR> ... </TR> specifies a table row within a table. You may define<br> default attributes for the entire row: ALIGN (LEFT, CENTER,<br> RIGHT) and/or VALIGN (TOP, MIDDLE, BOTTOM). See Table<br> Attributes at the end of this table for more information.<br> <TH> ... </TH> defines a table header cell. By default the text in this<br> cell is bold and centered. Table header cells may contain<br> other attributes to determine the characteristics of the<br> cell and/or its contents. See Table Attributes at the end<br> of this table for more information.<br> <TD> ... </TD> defines a table data cell. By default the text in this cell<br> is aligned left and centered vertically. Table data cells<br> may contain other attributes to determine the<br> characteristics of the cell and/or its contents. See Table<br> Attributes at the end of this table for more information.</font></p> <p><font face="Verdana"> <b> Table Attributes</b></font></p> <p><font face="Verdana">NOTE: Attributes defined within <TH> ... </TH> or <TD> ... </TD> cells<br> override the default alignment set in a <TR> ... </TR>.<br> Attribute<br> Description<br> * ALIGN (LEFT, CENTER, RIGHT)</font></p> <p><font face="Verdana"> * VALIGN (TOP, MIDDLE, BOTTOM)</font></p> <p><font face="Verdana"> * COLSPAN=n</font></p> <p><font face="Verdana"> * ROWSPAN=n</font></p> <p><font face="Verdana"> * NOWRAP<br> * Horizontal alignment of a cell.</font></p> <p><font face="Verdana"> * Vertical alignment of a cell.</font></p> <p><font face="Verdana"> * The number (n) of columns a cell spans.</font></p> <p><font face="Verdana"> * The number (n) of rows a cell spans.</font></p> <p><font face="Verdana"> * Turn off word wrapping within a cell.</font></p> <p><font face="Verdana">General Table Format</font></p> <p><font face="Verdana">The general format of a table looks like this:</font></p> <p><font face="Verdana"><TABLE> <== start of table definition</font></p> <p><font face="Verdana"><CAPTION> caption contents </CAPTION> <== caption definition</font></p> <p><font face="Verdana"><TR> <== start of first row definition<br> <TH> cell contents </TH> <== first cell in row 1 (a head)</font></p> <p><font face="Verdana"><TH> cell contents </TH> <== last cell in row 1 (a head)<br> </TR> <== end of first row definition</font></p> <p><font face="Verdana"><TR> <== start of second row definition<br> <TD> cell contents </TD> <== first cell in row 2</font></p> <p><font face="Verdana"><TD> cell contents </TD> <== last cell in row 2<br> </TR> <== end of second row definition</font></p> <p><font face="Verdana"><TR> <== start of last row definition<br> <TD> cell contents </TD> <== first cell in last row<br> ...<br> <TD> cell contents </TD> <== last cell in last row<br> </TR> <== end of last row definition</font></p> <p><font face="Verdana"></TABLE> <== end of table definition</font></p> <p><font face="Verdana">The <TABLE> and </TABLE> tags must surround the entire table definition. The<br> first item inside the table is the CAPTION, which is optional. Then you can<br> have any number of rows defined by the <TR> and </TR> tags. Within a row you<br> can have any number of cells defined by the <TD>...</TD> or <TH>...</TH><br> tags. Each row of a table is, essentially, formatted independently of the<br> rows above and below it. This lets you easily display tables like the one<br> above with a single cell, such as Table Attributes, spanning columns of the<br> table.</font></p> <p><font face="Verdana"><b>Tables for Nontabular Information</b></font></p> <p><font face="Verdana">Some HTML authors use tables to present nontabular information. For example,<br> because links can be included in table cells, some authors use a table with<br> no borders to create "one" image from separate images. Browsers that can<br> display tables properly show the various images seamlessly, making the<br> created image seem like an image map (one image with hyperlinked quadrants).</font></p> <p><font face="Verdana">Using table borders with images can create an impressive display as well.<br> Experiment and see what you like.</font></p> <p><font face="Verdana"> <b> Fill-out Forms</b></font></p> <p><font face="Verdana">Web forms let a reader return information to a Web server for some action.<br> For example, suppose you collect names and email addresses so you can email<br> some information to people who request it. For each person who enters his or<br> her name and address, you need some information to be sent and the<br> respondent's particulars added to a data base.</font></p> <p><font face="Verdana">This processing of incoming data is usually handled by a script or program<br> written in Perl or another language that manipulates text, files, and<br> information. If you cannot write a program or script for your incoming<br> information, you need to find someone who can do this for you.</font></p> <p><font face="Verdana">The forms themselves are not hard to code. They follow the same constructs<br> as other HTML tags. What could be difficult is the program or script that<br> takes the information submitted in a form and processes it. Because of the<br> need for specialized scripts to handle the incoming form information,<br> fill-out forms are not discussed in this primer. Check the Additional Online<br> Reference section for more information.</font></p> <p><font face="Verdana"> <b> Troubleshooting</b></font></p> <p><font face="Verdana">Avoid Overlapping Tags</font></p> <p><font face="Verdana">Consider this example of HTML:</font></p> <p><font face="Verdana"> <B>This is an example of <DFN>overlapping</B> HTML tags.</DFN></font></p> <p><font face="Verdana">The word overlapping is contained within both the <B> and <DFN> tags. A<br> browser might be confused by this coding and might not display it the way<br> you intend. The only way to know is to check each popular browser (which is<br> time-consuming and impractical).</font></p> <p><font face="Verdana">In general, avoid overlapping tags. Look at your tags and try pairing them<br> up. Tags (with the obvious exceptions of elements whose end tags may be<br> omitted, such as paragraphs) should be paired without an intervening tag in<br> between. Look again at the example above. You cannot pair the bold tags<br> without another tag in the middle (the first definition tag). Try matching<br> your coding up like this to see if you have any problem areas that should be<br> fixed before your release your files to a server.</font></p> <p><font face="Verdana">Embed Only Anchors and Character Tags</font></p> <p><font face="Verdana">HTML protocol allows you to embed links within other HTML tags:</font></p> <p><font face="Verdana"> <H1><A HREF="Destination.html">My heading</A></H1></font></p> <p><font face="Verdana">Do not embed HTML tags within an anchor:</font></p> <p><font face="Verdana"> <A HREF="Destination.html"><br> <H1>My heading</H1><br> </A></font></p> <p><font face="Verdana">Although most browsers currently handle this second example, the official<br> HTML specifications do not support this construct and your file will<br> probably not work with future browsers. Remember that browsers can be<br> forgiving when displaying improperly coded files. But that forgiveness may<br> not last to the next version of the software! When in doubt, code your files<br> according to the HTML specifications (see For More Information below).</font></p> <p><font face="Verdana">Character tags modify the appearance of the text within other elements:</font></p> <p><font face="Verdana"> <UL><br> <LI><B>A bold list item</B><br> <LI><I>An italic list item</I><br> </UL></font></p> <p><font face="Verdana">Avoid embedding other types of HTML element tags. For example, you might be<br> tempted to embed a heading within a list in order to make the font size<br> larger:</font></p> <p><font face="Verdana"> <UL><br> <LI><H1>A large heading</H1><br> <LI><H2>Something slightly smaller</H2><br> </UL></font></p> <p><font face="Verdana">Although some browsers handle this quite nicely, formatting of such coding<br> is unpredictable (because it is undefined). For compatibility with all<br> browsers, avoid these kinds of constructs. (The Netscape <FONT> tag, which<br> lets you specify how large individual characters will be displayed in your<br> window, is not currently part of the official HTML specifications.)</font></p> <p><font face="Verdana">What's the difference between embedding a <B> within a <LI> tag as opposed<br> to embedding a <H1> within a <LI>? Within HTML the semantic meaning of <H1><br> is that it's the main heading of a document and that it should be followed<br> by the content of the document. Therefore it doesn't make sense to find a<br> <H1> within a list.</font></p> <p><font face="Verdana">Character formatting tags also are generally not additive. For example, you<br> might expect that:</font></p> <p><font face="Verdana"> <B><I>some text</I></B></font></p> <p><font face="Verdana">would produce bold-italic text. On some browsers it does; other browsers<br> interpret only the innermost tag.</font></p> <p><font face="Verdana">Do the Final Steps</font></p> <p><font face="Verdana"><b>Validate Your Code</b></font></p> <p><font face="Verdana">When you put a document on a Web server, be sure to check the formatting and<br> each link (including named anchors). Ideally you will have someone else read<br> through and comment on your file(s) before you consider a document finished.</font></p> <p><font face="Verdana">You can run your coded files through an HTML validation service that will<br> tell you if your code conforms to accepted HTML. If you are not sure your<br> coding conforms to HTML specifications, this can be a useful teaching tool.<br> Fortunately the service lets you select the level of conformance you want<br> for your files (i.e., strict, level 2, level 3). If you want to use some<br> codes that are not officially part of the HTML specifications, this latitude<br> is helpful.</font></p> <p><font face="Verdana"><b>Dummy Images</b></font></p> <p><font face="Verdana">When an <IMG SRC> tag points to an image that does not exist, a dummy image<br> is substituted by your browser software. When this happens during your final<br> review of your files, make sure that the referenced image does in fact<br> exist, that the hyperlink has the correct information in the URL, and that<br> the file permission is set appropriately (world-readable). Then check online<br> again!</font></p> <p><font face="Verdana"><b>Update Your Files</b></font></p> <p><font face="Verdana">If the contents of a file are static (such as a biography of George<br> Washington), no updating is probably needed. But for documents that are time<br> sensitive or covering a field that changes frequently, remember to update<br> your documents!</font></p> <p><font face="Verdana">Updating is particularly important when the file contains information such<br> as a weekly schedule or a deadline for a program funding announcement.<br> Remove out-of-date files or note why something that appears dated is still<br> on a server (e.g., the program requirements will remain the same for the<br> next cycle so the file is still available as an interim reference).</font></p> <p><font face="Verdana"><b>Browsers Differ</b></font></p> <p><font face="Verdana">Web browsers display HTML elements differently. Remember that not all codes<br> used in HTML files are interpreted by all browsers. Any code a browser does<br> not understand is usually ignored though.</font></p> <p><font face="Verdana">You could spend a lot of time making your file "look perfect" using your<br> current browser. If you check that file using another browser, it will<br> likely display (a little or a lot) differently. Hence these words of advice:<br> code your files using correct HTML. Leave the interpreting to the browsers<br> and hope for the best.</font></p> <p><font face="Verdana"><b>Commenting Your Files</b></font></p> <p><font face="Verdana">You might want to include comments in your HTML files. Comments in HTML are<br> like comments in a computer program--the text you enter is not used by the<br> browser in any formatting and is not directly viewable by the reader just as<br> computer program comments are not used and are not viewable. The comments<br> are accessible if a reader views the source file, however.</font></p> <p><font face="Verdana">Comments such as the name of the person updating a file, the software and<br> version used in creating a file, or the date that a minor edit was made are<br> the norm.</font></p> <p><font face="Verdana">To include a comment, enter:</font></p> <p><font face="Verdana"> <!-- your comments here --></font></p> <p><font face="Verdana">You must include the exclamation mark and the hyphens as shown.</font></p> <p><font face="Verdana"> <b>For More Information</b></font></p> <p><font face="Verdana">This guide is only an introduction to HTML, not a comprehensive reference.<br> Below are additional online sources of information. Remember to check a<br> bookstore near you for Web and HTML books.</font></p> <p><font face="Verdana"><b>Style Guides</b></font></p> <p><font face="Verdana">The following offer advice on how to write "good" HTML:</font></p> <p><font face="Verdana"> * Composing Good HTML<br> * W3C's style guide for online hypertext</font></p>
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