Check if the browsers supports SVG

gistfile1.js

// comments welcome, there may be better ways to do this!

function supportsSVG(){
 return !!('createElementNS' in document &&
   document.createElementNS('http://www.w3.org/2000/svg','svg').createSVGRect)
}

I'm looking for an as-short-as-possible snippet that reliably detects support for SVG.

You can crunch this down a bit to be

function supportsSVG(a,b){return !!((b='createElementNS') in (a=document) && a[b]('http://www.w3.org/2000/svg','svg').createSVGRect)}

Which saves 9 bytes - if that's what you want.