Today’s HTML tag we review for its SEO influence is the <!doctype> tag:
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
For more information on how to use the doctype depending on the version of the html you’re using, visit http://www.w3.org/QA/2002/04/valid-dtd-list.html
What designers should know about the doctype tag in terms of SEO
When you cut your psd file into html/css yo need to add this piece of code on the very top of each page.
What SEOs should know about the doctype tag
The doctype document is not having any influence on your SEO job. However, make sure the designer added the tag on all page. Ohterwise, don’t mind about it.
What programmers should know about doctype
This tag is your responsibility. Make sure you it is present on all pages. Without the doctype declaration you won’t be able to check the validity of your documents. Once you declared the doctype and you think you’re done with your programming part go to http://validator.w3.org/. See, you only thought you’re done. Fix all issues – missed alt text, duplicate ids ans deprecated tags. You may want to check your website for accessibility issues also (once you are html/css/accessibility valid) you can you W3 trust logos on your site footer (if it makes sense, i.e. you have IT portfolio website)
What copywriters should know
Don’t mind about this tag. You keep working on original, quality content for the website