Which SVG support detection method is best? [closed]

Question

Somebody has already asked my question about detecting SVG support in browsers but there are three leading solutions and not a lot of discussion about the merits of each.

So: which, if any, is best? In terms of portability and correctness, that is. False negatives (i.e. "no svg") are undesirable, but acceptable; false positives are not.

Exhibit A:

var testImg = 'data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIyNzUiIGhlaWdodD0iMjc1Ij48L3N2Zz4%3D';

var img = document.createElement('img')

img.setAttribute('src',testImg);

return img.complete; 

Exhibit B:

return document.implementation.hasFeature(
    "http://www.w3.org/TR/SVG11/feature#BasicStructure", "1.1");

Exhibit C:

return !! document.createElementNS &&
       !! document.createElementNS (
             'http://www.w3.org/2000/svg',
             "svg")
      .createSVGRect;

Lundt

What are your fitness criteria for 'best'? Perhaps you should modify your question and title to ask specific, answerable questions like "Will any of these fail (return a false negative or positive) in any browsers released in the last 3 years?" or some such. Otherwise this question is ripe for closing as subjective. – Bilge

Exhibit B is deprecated. – Mccabe

Answer 1

I would probably use modernizr.

Freida

Looks like that's the same as C underneath. – Lundt

Not a very useful answer, unless you care to explain which method modernizr uses and why it is better. Feature detection need not rely on a library, and the library must use some sort of detection itself. – Delitescent

Answer 2

No need to include the entire Modernizr library for this. Here's a simple check that I've used in the past:

typeof SVGRect !== "undefined"; // true if supported, false if not

This quite simply checks for support of the SVGRect object which is defined in the SVG Specification. In Chrome, typeof SVGRect is "function" and in IE9 it's "object", but in browsers which do not support SVG (IE8, for instance) this returns "undefined".

With the above code, you can simply:

if (typeof SVGRect !== "undefined") { ... /* If the browser does support SVG. */ }
else { ... /* If the browser does not support SVG. */ }

Promontory

Is this an accurate test for determining if the browser supports svg within an img tag? <img src="file.svg">? Are there browsers that support svg images via img src, while also NOT supporting the modern API for programmatically drawing them? – Mccabe

Answer 3

Currently, Modernizr uses approach B to detect for support for SVGs in <img> tags, and approach C to detect for support for SVGs in <embed> and <object> tags. It seems it used to use an approach that was more like A for detecting for "SVG as img" support, but that was dropped in favour of B (for more detail, see this post on CSS-tricks).

Consequently, it seems that at the moment, either B or C would be the best approach, depending on what exactly you want to test for.

Kyne