gistfile1.js

    /*
    Change menu background
    */
    if ( !$.browser.msie || !$.browser.mozilla ) {
        html2canvas(document.body, {
            onrendered: function(canvas) {
                var str = canvas.toDataURL();
                $('body').append('<div id="blur_menu_bg"></div>');
                $('#blur_menu_bg').css('background-image', 'url(' + str + ')');
                $('.bg').blurjs({
                    source: '#blur_menu_bg',
                    // draggable: true,
                    radius: 15,
                    overlay: 'rgba(222,222,222,0.7)'
                });
                $(window).scroll(function() {
                    //console.log($('.menu').offset().top);
                    var ofs = $('.bg').offset().top - 30;
                    //console.log(ofs);
                    $('.bg').css('background-position', '0px -' + $('.bg').offset().top + 'px');
                });
            }
        })
    }