Why do some major websites use invalid HTML?

Question

I noticed that many websites, even Google and some banking sites, have poorly-written HTML with no quotes around the values of attributes, or using characters such as ampersands not escaped correctly in links. In other words, many use markup that would not validate.

I am curious about their reasons. HTML has simple rules and it is just mind-boggling that they don't seem to follow those rules. Or do they use programs that just spit out the code?

Answer 1

For several websites such as Google, having perfect code is not "that" important.

The total size of the web-page however, is. A few bytes spared on the HTML code can mean hundreds of dollars in bandwidth.

So if they can be certain their page will be rendered correctly, they won't hesitate to tweak their HTML.

Answer 2

Generally speaking, coding up a website is easy and therefore the entry barrier is very low for inexperienced or non programmers. This makes it easy to produce sub standard pages and the web is littered with them. Combine that with tools like Microsoft Frontpage that makes it even easier to make a site (and even easier to generate bad HTML code) and you've got a nasty situation.

Answer 3

As been discussed previously, google does it for bandwidth reasons.

As for banks and other enterprisey websites, there could be multiple reasons-

1. CMS spits out invalid HTML
2. Dreamweaver, enough said.
3. Tend to use commercial UI components that have been designed to work even on ancient browsers so they err on the careful side.
4. No emphasis on good HTML and Javascript practices. Many of them tend to be Java or .NET shops with no good UI developers.
5. Badly designed .NET User controls and JSTL taglibs.

Answer 4

The nice thing about standards is that you have so many to choose from.