What is Validation?
Due to advances in technology and accessibility, it is important that you validate your web pages. The W3C’s Markup Validation Service is a free service that checks and verifies your HTML, XHTML, CSS, etc so that it meets current web design standards. Having valid code on your page makes sure you haven’t misspelled or mistyped anything (or much) and it will help guartanee that your pages will work in “all” browsers. However, you may need to add some hacks so IE 5 and 6 render your CSS correctly; those hacks will NOT validate. You must make a choice. Either way, it is really important to validate your pages if you want a quality web site, and you want a quality site that will draw visitors, right?
Start with a Doctype
Make sure you have a document type definition in your XHTML or HTML pages. This tells the validator what standards to use. YOU set up the standards you are using by adding a doctype. This code is usually the very first line in your web page. It goes above the html tag.
HTML 4.01 Transitional:
< !DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
HTML 4.01 Strict:
< !DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
XHTML 1.0 Transitional
< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
XHTML 1.0 Strict
< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
XHTML 1.1
< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
XHTML Mobile
< !DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.0//EN" "http://www.wapforum.org/DTD/xhtml-mobile10.dtd">
HTML Specification
In your HTML opening tag, add the following specification.
Character Encoding
Add a META tag inside your body tag that indicates what language you are using in your web page.
Use the W3C’s Validation Service
Next, you upload your file to the validtor webpage or state the URL of your file in the validator web page.
Once you hit the Check button, the web site will go through your code and check to see if your code correctly validates with your doctype. If you do not specify a doctype in HTML, then it will throw that error and validate according to its default doctype. If you have errors, the page will return a detailed list complete with line number. Use this information to fix and improve your code to make it more accessible and usable across different browsers.
You can then recheck your pages to update the error list or to see if all your fixes are valid, too.
If everything is valid, you get a nice congratulatory message.
