Capsule shape using border-radius without a set width or height?

Question

Is it possible to make a capsule shape using border-radius without a set width or height?

I want the left and right sides to be completely rounded while the capsule would remain straight along it's horizontal length. Setting the radius to 50% doesn't seem to give the desired affect.

Answer 1

Applying a very large border radius seems to work on many browsers (IE9+, FF, Chrome) like this mod of David's fiddle http://jsfiddle.net/cthQW/1/

border-radius: 500px; 

Answer 2

Yes, this is possible (albeit I've only tested in Chromium 28/Ubuntu 12.10):

div {     /* this is the only relevant part: */     border-radius: 20%/50%;      /* this is irrelevant, and just so the element can be visualised/displayed: */     width: 50%;     height: 5em;     margin: 2em auto;     background-color: #000; } 

JS Fiddle demo.

The important information is, obviously, the 20%/50% property-value; the 20% is the 'horizontal length' of the radius, whereas the 50% is the 'vertical length'; using two different measurements gives an elliptical curve to the border, instead of a single measurement, which yields the more circular radius. Obviously this requires a certain amount of adjustment to your own requirements

References:

• border-radius (at Mozilla Developer Network).
• CSS Backgrounds and Borders Module Level 3: 5.1. Curve Radii: the ‘border-radius’ properties.