HTML – HyperText Markup Language – is a page description language used to write the web pages that make up the World Wide Web. As the name implies, with HTML you can mark different pages of a page, for example what should be a heading, a new paragraph, italicized text and the like. You can also place images, tables and some other features, but unfortunately you do not have the same control over the page’s appearance as in advanced layout programs.
Acronym Source: https://www.abbreviationfinder.org/acronyms/html.html
The basic idea behind HTML is the following. If you create sophisticated pages, with exotic fonts, images, columns, footnotes and other neatly, in an advanced word processing program (eg MS Word), these programs usually save information about the page layout and formatting using the control codes embedded in the file. The disadvantage of these control codes is partly that they are different for the different programs, but also that some of these special codes have a tendency not to survive transmission over networks. Better then, as in HTML, to insert the formatting instructions in plain text in the file, in the form of codes written with characters that survive network transport.
Also important with HTML is that it is an open standard, ie it is owned by no one, and therefore no one has to pay a license to companies like Microsoft or Adobe in order to make programs that support HTML, such as web browsers. This promotes the development of new and inexpensive software for the World Wide Web.
HTML LIMITATIONS
With HTML you can then look up your sad text by inserting some formatting codes and looking at the page through an HTML interpreter, ie a browser. Unfortunately, as a formatting language, HTML is rather primitive, and anyone who is used to real layout programs’ ability to accurately determine the position of text or images on the page, change fonts, add text and image over one another, is probably quite frustrated in the encounter with HTML. But you actually come a long way with HTML anyway, if you just learn to accept and handle its limitations.
The limitations of the web writer’s ability to create refined web pages are mainly of three types:
The user can set certain parameters:
One of the basic ideas behind HTML is that only what really needs to be transmitted over the web – namely the content – should be placed in the HTML code, and as much as possible of the form, the receiving and interpreting browser should perform itself. The user can configure his web application (in Netscape: look in the Options: Preferences menu) and specify, for example, the font, the degree (size) for body text, how links are to be displayed etc. The website author can only determine the relative size and style for eg headings and body text. Above all, it is the user and not the author who controls the width of the window (= page), which makes page layout extremely frustrating. For example, a designer may be pleased to see his beautiful page in a way in his browser, but a user like t.
Different browsers interpret the HTML code differently:
A surprise to most is that the HTML standard does not rigorously define how different tags should be interpreted by a browser. The only paragraph separator <P> expected to do is to mark a new paragraph. If this is then done by inserting a blank line between the paragraphs, or the new paragraph just being added to a new line, somewhat indented, it is up to the manufacturers of the web programs to decide. Other elements that are usually interpreted differently are the indentation of lists and the handling of images. Again: the web designer does not have full control over the appearance of his site.
HTML doesn’t actually do everything:
The third and obvious limitation comes from the fact that the designers of HTML have not added, or even want to insert all possible possibilities for word, image and layout management in HTML. This is partly because the web is not burdened with overly heavy and complicated code-packed pages, and partly because it may not even be necessary for web pages to look perfect – the content can probably be presented even without the nicest possible packaging.
Example
Before: UNFORMATED TEXT
HTML
Pages on the World Wide Web are written in a page description language called HTML, which means HyperText Markup Language. Learning HTML and writing your own web pages is quite fast.
You don’t need any tools other than a regular text editor for writing, and a browser to test how the page turned out.
MARKING
<H2> HTML </ H2>
Pages on & aring; <A HREF=”omwww.html”> World Wide
Web </A> is written in a page description language;
called HTML, which means <I> HyperText Markup
Language </ I>. It does pretty quickly
learn HTML and write your own web pages.
<P>
No other remedies are needed
and a regular text editor for writing,
and a web browser to test how
page turned.
After: FORMATTED TEXT!
HTML
Pages on the World Wide Web are written in a page description language called HTML, which means HyperText Markup Language . Learning HTML and writing your own web pages is quite fast.
You don’t need any tools other than a regular text editor for writing, and a browser to test how the page turned out.
XML
What is XML? / How does XML work?
XML stands for eXtensible Markup Language and is a method for structuring data in a text file. The method can thus be very useful for tree and hierarchical structures and other types of data that may need to be organized such as address books, family trees and technical drawings.
Just like HTML , XML uses tags (words preceded by ‘<‘ and ends with ‘>’) and attributes (according to the form name = ”value”), but the differences in usage are large. HTML uses tags and attributes to specify functionality that affects the content between them, such as how the text will look like in the browser .. XML instead uses tags to delimit the data, and instead let the application that reads the document determine the interpretation to be made. This means that the tags we previously learned in HTML can have any meaning in XML .
Ex : HTML tagging <b> </b> means that the text that is between start and end tag will be bold, but in XML it could mean, for example, that it is the title of a book or the name of a biological organism. Thus, one cannot be limited by predefined tags but rename them to what is desired in order to have an easily understandable structure.
Because XML files are text files that are meant to be read by people, they are very easy to handle. You can thus, in the same way as with HTML, edit code and adjust errors directly in any text editor, but XML uses a strict debug method that gives error messages if a start tag lacks a closing tag or if an attribute lacks a quotation. This means that you can quickly detect errors, and that you get a document with good structure.
What is less straightforward is the creation of applications that will read the XML data, for example, scripts of different kinds (eg javascript). Thus, if you do not want to use any pre-built parser, which otherwise only works in InterNet Explorer 5 and Netscapes Pre-Release 6, then it will be quite complicated (see upcoming demo!).
When XML was created you were aware that the text format would produce larger files than binary format does, but it was considered more important to have code that is easy to read for users and that the files take up space is considered a minor problem as most have plenty of disk space .
XHTML
XHTML (Extensible Hyper Text Markup Language) is a reformulation of HTML 4.0 as an application to XML (Extensible Markup Language) .
XHTML is the subsequent version of HTML 4.0 . You can say HTML5 . In XHTML , all the tags and attributes that exist previously exist. Unlike HTML , XHTML can be expanded / expanded by anyone using it. New attributes and tags can be defined and added to those that already exist.
XHTML 1.0 is the first step towards a modular and extensible “web” based on XML .
Why is XHTML better than HTML?
The most common reason for upgrading to a new language version is to be able to take advantage of new technologies and also that problems with the previous versions have been fixed.
Expandability:
HTML -en SGML application requires a revision of the entire DTD (Document Type Definition) , the addition of a new group of elements. XML is a simplified subset of SGML. This simplifies the development and integration of new collections of elements.
Portability:
By 2002, as much as 75% of internet access will be able to be performed by non-PC platforms such as “palm computers”, television, refrigerators, telephones, etc. In most cases, these devices will not be able to hold the same “computing power” as desktop computers. , and will not be designed to handle “non-well-formed” HTML as current “web” readers do.
If we look at these two points above , HTML does not completely lack these attributes. The problem lies in the slow development relative to the development of the internet and how difficult it can be to create pages that work well on a wide range of “web” readers and platforms. With XHTML , help with these problems is obtained.
Why was XHTML created, and why do we need it?
Although HTML has been very useful and successful, the language is no longer suitable as a basis for the development of commercial and industry “web” -based applications on the Internet and intranet.
HTML was originally created for a diverse environment from today’s very demanding “high-tech” internet. The purpose was mainly for the exchange of data and documents between scientists.
Over time, the language has been drawn out “sea”, which has made it difficult or almost impossible for user agents, such as web browsers, to interpret it. After a decade of use and temporary, random development, it is desirable with a more expandable and more protable language.
The current issue is to facilitate the transition from HTML to all users who are at home on HTML. Creating HTML in XML seems to be in demand. The result is XHTML, a custom application of XML to express WEB pages.
With HTML, creators have only a fixed amount of elements to utilize without variation. But with XHTML, anyone can expand the elements – new tags and attributes can be defined and applied to the existing ones, which allows new paths to be developed when developing WEB pages. With XHTML 1.0, creators can combine known HTML 4 elements with elements from other XML languages.
Differences between HTML 4 and XHTML.
Tags and attributes must be written with small letters:
Because XML is sensitive to upper or lower case letters, XHTML elements and attribute names must be written in lower case. Attribute values can be selected either large or small (ie in the example below, both attributes – “# ffcc33” and “# FFCC33” – are allowed).
Ex :
| HTML | XHTML |
| <TD BGCOLOR = ”# ffcc33”> | <td bgcolor = ”# ffcc33”> |
Elements must be nested, not overlapped:
Most web browsers do not care if elements overlap. For example. if a “bold” (<b>) tag is placed at the end of a “paragraph” (<p>), it does not matter which of the tags </b> or </p> is closed first. When using XML and XHTML, tags must be closed in reverse order – first opened – first closed.
Ex :
| HTML | XHTML |
| <p> New <b> media! </p> </b> | <p> New <b> media! </b> </p> |
All non-empty elements must be closed:
All elements must be closed, explicit or implicit.
Affected elements: <basefont>, <body>, <colgroup>, <dd>, <dt>, <head>, <html>, <li>, <p>, <tbody>, <thead>, <tfoot> , <th>, <td>, <tr>.
Ex :
| HTML | XHTML |
First paragraph <p>Second paragraph <p> |
<p> First paragraph </p><p> Second paragraphs </p> |
Empty elements must be closed:
Empty elements, those without a closing tag, have no content. While a <p> tag contains a paragraph and a <b> tag contains text that should be “rough (or colorful)”, a <br> tag is empty because it never contains anything. Other empty tags are <hr> and <img src = ”xxx.gif”>. In XML, all empty elements must use the “/” character before the closing hook (“>”).
(Note in the example below the space after the element text and “/>”. This is for compatibility with the current web browser.)
Ex :
| HTML | XHTML |
| <Hr><br>
<img src = ”xxx.gif”> |
<hr /><br /> <igm src = ”xxx.gif” /> |
Attributes must be quoted:
Each attribute must be quoted, even if it is numeric.
Ex :
| HTML | XHTML |
| <img … border = 0> | <img … border = ”0” /> |
Attributes – value pairs cannot be minimized :
An attribute is minimized when there is only one possible value. Unlike HTML, this is not allowed. Single attributes must be expanded.
Ex :
| HTML | XHTML |
| <dl compact><ul compact>
<option… selected> <td nowrap> text </td> <input type = ”checkbox”… checked> |
<dl compact = ”compact”><ul compact = ”compact”>
<option… selected = ”selected”> <td nowrap = ”nowrap”> text </td> <input type = ”checkbox”… checked = ”checked” /> |