Uses for the '"' entity in HTML

Question

I am revising some XHTML files authored by another party. As part of this effort, I am doing some bulk editing via Linq to XML.

I\'

Answer 1

Reason #1

There was a point where buggy/lazy implementations of HTML/XHTML renderers were more common than those that got it right. Many years ago, I regularly encountered rendering problems in mainstream browsers resulting from the use of unencoded quote chars in regular text content of HTML/XHTML documents. Though the HTML spec has never disallowed use of these chars in text content, it became fairly standard practice to encode them anyway, so that non-spec-compliant browsers and other processors would handle them more gracefully. As a result, many "old-timers" may still do this reflexively. It is not incorrect, though it is now probably unnecessary, unless you're targeting some very archaic platforms.

Reason #2

When HTML content is generated dynamically, for example, by populating an HTML template with simple string values from a database, it's necessary to encode each value before embedding it in the generated content. Some common server-side languages provided a single function for this purpose, which simply encoded all chars that might be invalid in some context within an HTML document. Notably, PHP's htmlspecialchars() function is one such example. Though there are optional arguments to htmlspecialchars() that will cause it to ignore quotes, those arguments were (and are) rarely used by authors of basic template-driven systems. The result is that all "special chars" are encoded everywhere they occur in the generated HTML, without regard for the context in which they occur. Again, this is not incorrect, it's simply unnecessary.