What Is DTD?
Keywords: DTD, Document Type Definition
I have been designing websites since 1996. In the beginning, it was so easy. Someone called me with a project, they sent me the content for their website, which I would then upload to Microsoft Frontpage or a text editor, insert some HTML tags for formatting and some graphics to make the site colorful, and the job was finished.
The wireless revolution changed everything. Almost every electronic device now comes equipped with access to the web and email. Palm tops, laptops, cell phones, even computer screens installed in automobiles are now connected to the internet. The web browsers and operating systems installed on these wireless devices are often very different from what is installed on an ordinary desktop PC. Many elements of the HTML programming language are not compatible with some of these wireless platforms. As a result, web design has completely changed. Cross-platform programming languages and specifications have been created so that websites can be viewed on any PC or wireless gadget.
These new innovations include languages such as XML, XHTML, and XSL, to name a few. XML was probably the most important of all of them, because it allowed a programmer to define data without telling the browser how to display it. The problem with HTML is that it defines data and also tells the browser how to display it. XML is different in that it merely defines the data, and allows the browser to display the data as it sees fit. Languages such as XHTML and XSL were developed in order to convert XML documents into web pages that could be displayed in a manner that was compatible with all browsers.
Now that you have some background on how and why web design has changed, you are now ready to learn about Document Type Definition (DTD). DTD is a tool that enables a programmer to define the format to be used for the data in an XML document. Remember, XML does not tell the web browser how to display or format content. DTD helps to establish the format.
An XML document consists of five different components. There are elements, attributes, entities, PCDATA, and CDATA. We will start with elements. Elements of XML are the tags. There are no predefined tags with XML; you can create your own tags. HTML does not work this way. All of the tags used in HTML are predefined, such as the paragraph tag and the body tag. Attributes provide additional information about the tags, such as the source file for an image, or the alignment to be used for a paragraph. Entities are variables that define commonly used text, such as the no-breaking-space entity. PCDATA is used to mark data that is to be parsed or separated into more easily processed components and to cause tags within that data to be interpreted as markup instead of as ordinary data. CDATA is used to mark data that is not to be parsed and to cause the tags within that portion of the text to not be treated as markup. As an aside, markup is any language that defines how cer
tain text is to be displayed or structured.
For novice programmers, DTD is a little hard to get used to. I recommend that you search for tutorials on any major search engine, or perhaps find some courses offline at a local college or computer science institute. If you have never studied XML, XHTML, or XSL before, then you should find a broad-based curriculum of computer programming courses that teach you all of these languages so that you can learn to incorporate them together when you create web sites.
Learning to use these new specifications and languages is essential for any web designer. With so many people using cell phones and other wireless devices to surf the net, by creating your web sites exclusively with HTML you run the risk of your site being invisible to a wireless internet user. Designing web sites that are cross-platform compatible is a must in the wireless age we now inhabit.
Jim Pretin is the owner of www.forms4free.com, a service that helps programmers make email forms.
Previous Articles Highlighter:
What Is RSS? (1)
Web browsers installed on wireless devices are often not compatible with many elements of the HTML programming language. However, all web browsers are compatible with XML, because XML files are simple text files; XML merely defines and lists data, it does not force the browser to display it in a certain way.
How To Hire The Right Web Designer (2)
A web designer who is part of a larger company that employs one hundred or more designers is just as bad as a freelancer. These sorts of web designers do not have much design skill, and are often given many different jobs to do at once.
What Is AJAX Programming? (3)
The drawbacks are that it can sometimes inhibit the use of the back button on the web browser, and sometimes the code has a problem initiating the response that it has been programmed to produce.
What Is XML Schema? (4)
XML Schema attributes are somewhat similar to HTML attributes in that they are included within a tag, and the attribute further defines the tag. With HTML, an image tag would have a source attribute to provide the name of the file that contains the image to be displayed.
Introduction To HTML DOM (5)
The document object gives birth, if you will, to the body object and all of the attributes and elements of the document. Here is an example of Document Object Model code that would be used to define the background color of an HTML document: Document.body.bgcolor In this example, document is the parent object, body is the child, and bgcolor is an attribute of the body object.
An Introduction To VBScript (6)
VBScript is a scripting language. Scripting languages are used to connect diverse pre-existing parts to accomplish a new related task without compiling. Also, scripting languages are interpreted, and are executed faster than a compiling language.
Introduction To SQL (7)
Here is an example of an SQL statement: SELECT Name,Height,Weight from BODY; This statement will retrieve all of the data from the Name, Height, and Weight columns contained within the table called Body.
What Is XML DOM? (8)
XML was probably the most important innovation of them all. XML enabled web designers to define data without telling the browser how to display the data, unlike HTML, which both defines the data and tells the browser how to display it.
What Is WSDL? (9)
Message defines the data elements and is akin to the parameters that are used in a function when a function is called. The third element is the types element.
What Are XForms? (10)
So, if you are a web designer or programmer, be wary of the fact that some people will not be accessing your forms from an ordinary PC. So, you should learn how to create XForms to accommodate your end user, so that the form will work properly regardless of what sort of device they might be using to surf the net.
What Is XSL? (11)
XML is a markup language just like HTML. XML was created to deal with the fact that HTML was limited in that all of its tags were predefined and it displayed data a certain way.
What Is SOAP? (12)
For example, when you log on to a website that provides real-time stock quotes and request the current market price for a certain stock, the price is fetched from a server that is constantly being updated with the latest price of each individual stock.
Is Pay-Per-Click Worth It? (13)
Just make sure that you bid within your budget and use specific keywords or phrases so that you'll receive qualified traffic, and you'll be fine. Jim Pretin is the owner of www.forms4free.com, a service that helps programmers make email forms.
What Is XML? (14)
Why do we need a more versatile specification like XML to describe data? After all, HTML works fine if used properly, so why do we need XML? Well, the answer is simple.
Broadband High Speed Internet: Choosing The Right Service (15)
T3/DS3 has a broadband speed of 44.736 Mbps digital circuit. It can be dedicated Internet access, point-to-point or integrated. Prices are approx. $5000-15,000 per month plus local loop.
Search Engine Optimization Tips For New Websites (16)
Those companies are household names, and they provide important services, so, naturally, a lot of websites link to them. For the other 99.9% of websites that don't do any real advertising offline, there are several ways to obtain a high number of inbound links.
Promoting Your MLM With Free Reports And Articles (17)
Check your facts, your statistics and make sure that what you write is exactly correct. Nothing will turn off a site user faster than to read what he/she thinks to be correct information only to find that what you've offered isn't what they need, or worse yet, isn't remotely correct.
Do You Really Have To Pay For Internet Marketing Knowledge? (18)
While a mentor can't do your homework for you or teach you everything you need to know, you have the benefit of the experience and wisdom of someone who's walked the walk you are beginning.
World Methanol Market Acquires New Characteristics (19)
However, the methyl alcohol consumption on the fuel market exhibits stagnant growth, which exerts an enormous downward pressure on prices paralleled by capacity expansion. Production of acetic acid remains a major methanol consumption sector.
How Affiliate Software Helps You To Succeed In Your Affiliate Business? (20)
When you work as an affiliate you usually sell a range of goods or services for profit. You will still have to work very hard to promote your business; however the financial risk to you is extremely low.
Newer Articles Highlighter:
A Brief Introduction To E4X (1)
Instead, Internet Explorer utilizes various programming components of a programming specification called AJAX, which uses a variety of languages, including JavaScript, XML, CSS, and several others. If you create web sites for a living, you should probably take some time to familiarize yourself with E4X.
What Is DHTML? (2)
Also, it is platform and language independent. This cross-platform compatibility is extremely significant because most wireless devices are now equipped with access to the internet and email. These wireless gadgets have installed on them web browsers and platforms that are not compatible with many elements of the basic HTML.
Choosing A Web Designer (3)
Also, it is extremely important to hire a designer who has a contract that you can sign that stipulates certain terms and conditions. You should be able to pay the designer 25% - 50% of the total quoted price up front, with the balance due upon completion.
Issues With Formmail (4)
The next challenge you will face is writing the code that will create the email message containing the answers to the form and send it to the email address you specified in your HTML code.
The Importance Of Link Popularity (5)
Some websites have thousands or even millions of sites linking to them, while others might have only 100 or less. The search engines use this as the most important criteria in their search algorithms for determining where a site should be ranked.
Can Anyone Really Make Money Online? (6)
The next most common scam you are likely to encounter is the MLM (Multi-Level-Marketing). These are companies that have some sort of product or service that they want you to sell.
A Guide To Internet Marketing (7)
If you are not patient enough to wait for your search engine ranking to improve, you can attract visitors to your web site instantly by using pay-per-click advertising (PPC). With PPC, you pay a certain cost per click to have an ad for your web page run at or near the top of the search engine listings for certain keywords.
Internet Marketing Made Simple (8)
Search engine optimization (SEO) is even more important. To optimize a site, you need to maximize your keyword density and optimize the positioning for the words or phrases for which you want to be listed.
Website Marketing Made Simple (9)
The first thing you need to understand is that your search engine ranking will not improve overnight. Be wary of Search Engine Optimization (SEO) consultants. They will charge you an arm and a leg for their services, sometimes as much as $2,000 per month or more.
An Introduction To Internet Marketing (10)
You can submit your site to free directories, or join a link exchange and trade links with other sites, or, you can author articles and press releases and submit them to article directories, who will then distribute your articles to webmasters looking for free content, who must link back to your website when they publish your article on theirs.
Introduction To Pay Per Click Marketing (11)
If you are operating a website for a small business, you need to diversify your internet marketing efforts by optimizing your website and increasing your link popularity so you can climb to the top of the search engines without having to pay for every click you receive.
Do You Need An HTML Form? (12)
There are also third-party HTML form services that will help you create the form and process it for you on their own servers. I hope this information will help you decide how you want to get an HTML form up and running on your website.
Improve Your Search Engine Ranking (13)
The next step is to submit your site to the search engines, if you have not already done so. It seems silly to mention this considering that we are talking about search engines anyway, but some people actually forget to submit their website to the engines, or only submit their site to a couple of search engines and then quit.
My Internet Marketing Secrets Revealed (14)
This is undoubtedly the best way to launch a business, but the costs are prohibitive. A full page ad in a prominent magazine or other publication can run as high as $50,000 per ad.
Getting Ranked Higher On Search Engines (15)
The only problem is no one will ever actually use that exact phrase when searching for auto insurance quotes, so even though the SEO company delivered on its promise to improve your ranking, you will still not receive any traffic.
Creating Your First HTML Form (16)
If you do not have the patience to do the work, use an outside service that creates the web form for you. Either way, it is important to have an HTML form so that people can contact you directly through your website.
HTML Might Become Obsolete (17)
So, it is imperative that most web designers learn to design web pages in XHTML. As almost every electronic device on the market is now equipped with internet access, it is important to use a versatile programming language like XHTML so that your web pages can be viewed and properly formatted across a wide variety of platforms.
Finding A Good Web Designer (18)
First of all, a freelancer is usually someone for who web design is merely a hobby. This sort of a person has probably taken a few courses in simple web design at a local institute or college, or might be self-taught, and dabbles in web design as a part-time job or a way to earn extra cash.
Your First Online Form (19)
As a result, those who have been spammed complain to their internet service provider, who then directs the complaint to the hosting company that handles your website. This can be a huge problem.
Learn How To Use Formmail (20)
If it does not include this code, you will need to hire a programmer to create it, or ask someone on a programming message board to help you with it.