.round-box {
    border-radius: 5px;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
}

This got me to wondering, does it support percentages as well? So I tried this:

.round-box {
    border-radius: 5%;
    -moz-border-radius: 5%;
    -webkit-border-radius: 5%;
}

This worked in Firefox 3.6 but not in Chrome. Some searching around revealed the Mozilla -moz-border-radius page. For border radius it specifically mentions that it supports length units as well as percentages:

A percentage, relative to the width of the box (the percentage is relative to the width even when specifying the radius for a height).

That page also mentioned support for elliptical borders. To do that you add another radius value separated by a slash:

.round-box {
    border-radius: 15px / 50px;
    -moz-border-radius: 15px / 50px;
    -webkit-border-radius: 15px / 50px;
}

The elliptical border worked on Chrome as well. If you bend this tight enough you can get pretty close to a circle.

I wanted Internet Explorer to add support for border radius before; now that I’ve got even more radius toys to play with I’m practically begging. I’m sorry Internet Explorer users but I’m tired of various border hacks when there are simple and clean CSS methods available.

Related posts:

1. Showing Your Last Tweet With Javascript
2. Browser Stats and Five Years of Firefox

Top 5 Browers

Top 5 Browsers, Bar Chart

Internet Explorer has 57.15%, Firefox 32.03% and then a virtual three way tie between Chrome (4.46%), Safari (3.58%), and Opera (2%). Here’s the bart chart version of this graph:

Top 5 Browsers, Line Chart

Browser Versions

Browser Versions, Line Chart

IE 7 at 22.73%, IE 8 at 19.46%, Firefox 3.5 at 19.32%, IE 6 at 14.94% (Ug!), Firefox 3.0 at 11.22%, Safari 4.0 at 3% and Firefox 2.0 at 1.28%. Everything else is below 1%. Here’s the bar chart version:

Browser Versions, Bar Chart

The good news is that IE 7, IE 8 and Firefox 3.0+ accounts for 72% of the browser market. The bad news is that IE 6 is still holding on at nearly 15%.

It would be great it other stats services like Google Analytics and Quantcast offered this view on the global browser market. Matt posted some browser stats for WordPress.com, which gets a pretty wide audience.

The only real browser stats that matter of course are the ones for your own site. Here’s the browser stats for josephscott.org (from Google Analytics):

Browser Stats - josephscott.org

Firefox at 58.34%, IE at 19.86%, Safari at 10.70%, and Chrome at 6.92%. The really good news is that IE 6 accounts for less than 4%. Here’s the breakdown for operating systems:

Operating System - josephscott.org visitors

Windows at 70.75%, Mac at 20.94%, and Linux at 7%. Out of the Windows users XP accounts for 65.33%, Vista 27.59%, NT (Seriously?) 4.84%, and Server 2003 at 1.52%. That’s a lot higher percentage for Mac and Linux than StatCounter Global Stats, which isn’t too surprising considering my blog posts skew more towards Mac and open source topics.

Related posts:

1. WordPress.com – 5 Million Blogs
2. Just Hanging Out
3. Google SEO

When using XMLHttpRequest, browsers implement POST as a two-step process (sending the headers first and then the data). This means that GET requests are more responsive – something you need in AJAX environments.

The claim is that even the smallest XHR will be sent using two packets if the request is done over HTTP POST instead of HTTP GET. I don’t remember ever having heard this claim before.

Let me first say that performance issues for POST vs. GET probably shouldn’t be your top factor for deciding which one to use. Make sure that you understand the implications of each and pick the right method for your request. For most people I suspect the biggest factor will involve caching, not performance. I was going to leave a comment on the article about this, but Simon beat me to it.

I wasn’t the only one who wanted to find out more about XHR POST using multiple packets. Fortunately someone else already asked that question and the author replied:

2. My claim is based on research done by Iain Lamb, cofounder of the Oddpost webmail startup that was acquired by Yahoo! and eventually became the basis for the all-new Yahoo! Mail.

His research showed “rather baffling finding: POST requests, made via the XMLHTTP object, send header and body data in separate tcp/ip packets [and therefore,] xmlhttp GET performs better when sending small amounts of data than an xmlhttp POST.”

That is why Yahoo includes the use of GET instead of POST as one of their high performance speed optimisation rules.

Simon Willison did some looking around and found more links for this. It was mentioned here and here, so it looks like Iain Lamb did do this research, even though I couldn’t find a first person account of it. This was enough information to make me curious, but not enough to answer all of my questions. It was time to run some tests of my own.

So I updated my install of Wireshark on Windows XP, turned off all of the packet reassembly options for HTTP decoding and started testing browsers. My very simple XHR POST test page looked like this:

<button type="button" onclick="$.post('hello.txt', {name: 'Joseph'})">XHR POST</button>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>

When the button is clicked an XHR POST request is made to hello.txt with the name=Joseph for a tiny amount of data. The domain I tested on sent along some cookies as well, but still left enough room for the tiny POST payload to fit in a single TCP packet.

Here are the results of the tests that I ran:

• IE 6 – 2 packets
• IE 7 – 2 packets
• IE 8 – 2 packets
• Firefox 3.0.13 – 1 packet
• Firefox 3.5.2 – 1 packet
• Opera 9.27 – 2 packets
• Safari 4.0.3 – 2 packets
• Chrome 2.0.172.43 – 2 packets

The short version of this is pretty easy to see, all of the browsers except for Firefox will use at least 2 packets for an XHR done over HTTP POST. When I saw that Safari sent 2 packets I figured that Chrome would as well, but I tested it anyway just to make sure.

I looked at the data size of each packet in IE 6; the first packet had 575 bytes of data and the second packet had 11 bytes of data. This lined up with the POST request which indicated that the content length was 11 bytes. The second packet consisted only of the POST data. Because Firefox sent less data in the user-agent string I increased the POST data so that it would exceed the combined total of the two IE packets to make sure I wasn’t running into any odd packet fragmentation. The second packet in Opera, Safari and Chrome was also only the 11 bytes of POST data.

If this were Myth Busters I’d call this myth confirmed. While it is true that not ALL browsers will always use two packets, it appears that the two packet process is the rule, not the exception. And with IE still the most widely used browser it’s very likely that a large portion of your users fall into the two packet category. If on the other hand 95% of your users happen to be using Firefox, then sure, you can skip thinking about this.

Related posts:

1. XHR / AJAX Performance – GET or POST?
2. Browser Stats and Five Years of Firefox
3. Recommended Reading: Steve Souders, High Performance Web Sites