JavaScript: Invert color on all elements of a page
javascript: (function ($) {
    function load_script(src, callback) {
        var s = document.createElement('script');
        s.src = src;
        s.onload = callback;
        document.getElementsByTagName('head')[0].appendChild(s);
    }

    function invertElement() {
        var colorProperties = ['color', 'background-color'];
        var color = null;
        for (var prop in colorProperties) {
            prop = colorProperties[prop];
            if (!$(this).css(prop)) continue;
            if ($(this).data(prop) != $(this).css(prop)) continue;

            if (($(this).css(prop) === 'rgba(0, 0, 0, 0)') || ($(this).css(prop) === 'transparent')) {
                if ($(this).is('body')) {
                    $(this).css(prop, 'black !important');
                    continue;
                } else {
                    continue;
                }
            }
            color = new RGBColor($(this).css(prop));
            if (color.ok) {
                $(this).css(prop, 'rgb(' + (255 - color.r) + ',' + (255 - color.g) + ',' + (255 - color.b) + ') !important');
            }
            color = null;
        }
    }

    function setColorData() {
        var colorProperties = ['color', 'background-color'];
        for (var prop in colorProperties) {
            prop = colorProperties[prop];
            $(this).data(prop, $(this).css(prop));
        }
    }

    function invertColors() {
        $(document).live('DOMNodeInserted', function(e) {
            var $toInvert = $(e.target).find('*').andSelf();
            $toInvert.each(setColorData);
            $toInvert.each(invertElement);
        });
        $('*').each(setColorData);
        $('*').each(invertElement);
        $('iframe').each(function () {
            $(this).contents().find('*').each(setColorData);
            $(this).contents().find('*').each(invertElement);
        });
    }
    load_script('http://www.phpied.com/files/rgbcolor/rgbcolor.js', function () {
        if (!window.jQuery) load_script('https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js', invertColors);
        else invertColors();
    });

})(jQuery);

//set up color properties to iterate through
var colorProperties = ['color', 'background-color'];

//iterate through every element
$('*').each(function() {
    var color = null;

    for (var prop in colorProperties) {
        prop = colorProperties[prop];

        //if we can't find this property or it's null, continue
        if (!$(this).css(prop)) continue;

        //create RGBColor object
        color = new RGBColor($(this).css(prop));

        if (color.ok) {
            //good to go, let's build up this RGB baby!
            //subtract each color component from 255
            $(this).css(prop, 'rgb(' + (255 - color.r) + ', ' + (255 - color.g) + ', ' + (255 - color.b) + ')');
        }
        color = null; //some cleanup
    }
});

javascript:function load_script(src,callback){var s=document.createElement('script');s.src=src;s.onload=callback;document.getElementsByTagName('head')[0].appendChild(s);}function invertColors(){var colorProperties=['color','background-color'];$('*').each(function(){var color=null;for(var prop in colorProperties){prop=colorProperties[prop];if(!$(this).css(prop))continue;color=new RGBColor($(this).css(prop));if(color.ok){$(this).css(prop,'rgb('+(255-color.r)+','+(255-color.g)+','+(255-color.b)+')');}color=null;}});}load_script('http://www.phpied.com/files/rgbcolor/rgbcolor.js',function(){if(!window.jQuery)load_script('https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js',invertColors);else invertColors();});

load_script('http://www.example.com/pixastic.invert.js', function () {$('img').each(function() {try{$(this).pixastic("invert");} catch(e) {}})})