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Comment by hinathan | Hacker News Reader

This is wrong on a lot of levels (x-platform, cpu usage, etc) but does make for such a pretty effect. Would be lovely if CSS(n+1) could support this kind of transform, especially to pull it out of the GPU instead of bit-banging through a <canvas/>

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SVG can do it: http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement

Unfortunately, browser support of less common SVG features is spotty – either missing or unoptimized.

This seems like it applies the filter to the entire element (including its children), which would not give the same effect as blur.js without some complicated absolute-positioning trickery.

You could do it like this with CSS, data URI and SVG:

    .blur {
      background-image: url('data:image/xml+svg;utf8,
        <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
          <defs>
            <filter id="f1">
              <feComponentTransfer>
                <feFuncR type="table" tableValues="0.5 1"/>
                <feFuncG type="table" tableValues="0.5 1"/>
                <feFuncB type="table" tableValues="0.5 1"/>
              </feComponentTransfer>
              <feGaussianBlur stdDeviation="5" /> 
            </filter>
          </defs>
    
          <image x="0" y="0" width="300" height="80" 
            xlink:href="http://background.png" 
            filter="url(#f1)" />
        </svg>
      ');
    }

(expanded for clarty, and I didn't test it so it may be buggy/not syntactically correct).

You can off course generate all that in JS and parametrize it.

It should work in Chrome, but won't in IE9. No idea for other browsers.

see http://jsfiddle.net/estelle/SJjJb/

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