invert.js

javascript:function bookmarklet_invert() {      var css = 'html {-webkit-filter: invert(100%);' +         '-moz-filter: invert(100%);' +          '-o-filter: invert(100%);' +          '-ms-filter: invert(100%); }',     head = document.getElementsByTagName('head')[0],     style = document.createElement('style');  if (!window.counter) { window.counter = 1;} else  { window.counter ++; if (window.counter % 2 == 0) { var css ='html {-webkit-filter: invert(0%); -moz-filter: invert(0%); -o-filter: invert(0%); -ms-filter: invert(0%); }'}  };  style.type = 'text/css'; if (style.styleSheet){   style.styleSheet.cssText = css; } else {   style.appendChild(document.createTextNode(css)); }  head.appendChild(style);  };bookmarklet_invert();