Possible Duplicate:
Blur Img's & Div's in HTML using CSS
So basically what I want to do is to blur content witch is behind a div element, that div is with opacity 0 – 0.5.
Here is a jsFiddle
EDIT[1]: What I actually want is that a div goes over an image and the area under the div is blured.
EDIT[2]: div with position: absolute goes over other elements and blur’s them.
You should blur image on upload. Then crop other image on upload (or crop it using jQuery/css). Then combine what you have to achieve this effect.
Using css for this task is impossible. Using javascript for this task is bad idea (very slow).
Only option is to use this technique on background image and then place another (cropped with js/upload) ontop of it.