The word semantic means, "of or relating to meaning," or the "study of meaning based on historical and psychologicalsignificance of words and terms." While this is all well and good, "the real world practice of marking up documents semantically follows the first definition." This was always ment to be the focus of HTML, but web designers in the past have always found ways around this to get their products out faster. However, with the advent of CSS, semantics is now back in contemporary webdesign. Changing the focus from "how our content looks, to what our content means."
As mentioned earlier, one of the biggest problems with web designers not likeing how something looks. "You want to use a heading, but you really dislike the font size that the h1 element produces, so you go with h3" because it looks nicer. The markup "was never ment to be presentational." Web devs used these "hacks" even after CSS came around, because "browser support was so maddeningly inaccurate and incomplete that it was downright unreliable to use CSS." H1, signifies "the most inmportant heading on the page, h2 is a subheading of h1 and so on." Many legacy tags have been replaced with the more accurate "em" (emphasis). This allows the CSS stylesheet to be able to specify what is ment.
The Web crawler or search-engine spider, "crawls" through the web to "read and index millions of webpages a day" to facilitate users with a searchable internet. These web crawlers "depend on the semantic clarity of web pages" to perform there scans. "In order for search engine spiders to be able to rate the significance of pieces of text they find in HTML documents, as well as for more automated agents as they are developed, the semantic structures that exist in HTML need to be widely and uniformly applied to bring out the meaning of published text." In 2010, Google specified "three forms of stuctured metadata that their systems will use to find structured semantic content within webpages. Google specifies that data may be given using microdata, microformats or RDFa."
"Web Content Accessibility Guidlines are part of a series of web accessibility guidlines published by the Web Accessibility Initiative (WAI) of the W3C." These guidlines are set in place for "people with disabilitiesand for user agents." In January of 2017, the US approved a final ruling to update Section 508 of the Rehabilitation Act of 1973. Sec 508 was "encated to eliminate barriers in information technology" to help disabled persons to use electronic media.