mark all border in page

markAllBackgrounds

//add javascript line into  your bookmark and click on a page
//known bug: if jquery is not loaded this will only work on the 2nd click

javascript: (function() {  if (!window.jQuery)  {      var script = document.createElement('script');  script.src="//ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js";  
document.body.appendChild(script);    }    if (window.markAllElementsBackground) {        $('*').each(function() {            $(this).css('background-color',$(this).data('save-background-color-data'))            });         window.markAllElementsBackground = false;     } else {        $('*').each(function() {            $(this).data('save-background-color-data', $(this).css('background-color')); var color = "#" + Math.floor(Math.random() * 0xFFFFFF).toString(16);$(this).css('background-color', color )});     window.markAllElementsBackground = true ;    }})();

markAllBorders

//add javascript line into  your bookmark and click on a page
//known bug: if jquery is not loaded this will only work on the 2nd click

javascript: (function() {  if (!window.jQuery)  {      var script = document.createElement('script');  script.src="//ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js";  
document.body.appendChild(script);    }    if (window.markAllElements) {        $('*').each(function() {            $(this).css('border',$(this).data('save-border-data'))            });         window.markAllElements = false;     } else {        $('*').each(function() {            $(this).data('save-border-data', $(this).css('border')); var color = "#" + Math.floor(Math.random() * 0xFFFFFF).toString(16);$(this).css('border','1px solid ' + color )});     window.markAllElements = true ;    }})();

using border can effects the elements because it added pixel to the border. it easy to replace the code to use background color instead of border

an example of the result:
in one click you get
https://www.dropbox.com/s/ohzr4nvavupmgb8/mark%20elements%20on%20page.PNG?dl=0
and in 2nd click you can return to regular state