Overhead of HTML whitespace indentation

Question

I started wondering what is the overall impact of using whitespaces to indent html documents.

Why not simply use tabs to indent? Wouldn't this be more cost-effective: 1 char (\t) vs. example 4 chars (spaces)?

I did little experimenting by converting an asp.net-page to use tabs and compared sizes of rendered markups. By replacing only one partial view's white space caused a page of 22kb size to be reduced to 19,4kb -> that's 12% reduction. Changing all indentation, page ended up allocating 16,7kb - 24% reduction! (used chrome dev tools and Fiddler for verifying)

Is my reasoning sound? Should tabs be used primary for indentation of HTML? Is there any reason to use spaces(such as compatibility with exotic browsers)?

ps. Stackoverflow seems to use spaces too. Converting SO main page to use tabs gave 9% reduction. Is this valid observation? If so, why haven’t they used tabs?

Answer 1

StackOverflow uses HTTP Compression - when this is turned on, the differences between using spaces versus tabs goes down - a lot.

You need to run your tests against the compressed versions for reliable results.

You do have a point though for the cases when a browser does not support the compression schemes the server supports.

Answer 2

First thing : html doesn't have a rule of doing indentation. It's done by programmers for code readability and program's structure. More ever We can reduce size taken by indents and white spaces by compression.

Minify/compact/compressing HTML : Compacting HTML code, can save many bytes of data and speed up downloading, parsing, and execution time.

StackOverflow uses HTTP Compression

Minifying HTML has the same benefits as those for minifying CSS and JS: reducing network latency, enhancing compression, and faster browser loading and execution. Moreover, HTML frequently contains inline JS code (in tags) and inline CSS (in tags), so it is useful to minify these as well.

Note: This rule is experimental and is currently focused on size reduction rather than strict HTML well-formedness. Future versions of the rule will also take into account correctness. For details on the current behavior, see the Page Speed wiki.

Tip: When you run Page Speed against a page referencing HTML files, it automatically runs the Page Speed HTML compactor (which will in turn apply JSMin and cssmin.js to any inline JavaScript and CSS) on the files and saves the minified output to a configurable directory.

Refer : http://code.google.com/speed/page-speed/docs/payload.html#MinifyHTML

Answer 3

Why not simply use tabs to indent? Wouldn't this be more cost-effective: 1 char (\t) vs. example 4 chars (spaces)?

If you're worried about downloaded HTML size, you won't fuss over tabs-vs-spaces — you'll compress your HTML as it goes over the wire and minify your markup, CSS, and Javascript, which provide real savings and don't interfere with your own coding guidelines.