zIndex-bookmarklet.js

// find all elements with a z-index and indicate what they are.

function contrast(color){ return '#' + 
   (Number('0x'+color.substr(1)).toString(10) > 0xffffff/2 ? '000000' :  'ffffff'); 
}

jQuery('*')
    .filter(function(){ return $(this).css('zIndex') !== 'auto'; })
    .each(function(){
         var color = '#'+Math.floor(Math.random()*16777215).toString(16); // <3 temp01
		 
         if ($(this).css('position').match(/absolute|relative/)) $(this).css('position','relative');
         $(this).css('border','1px solid '+color);
         $('<span>z-index: '+ $(this).css('zIndex') + '</span>')
           .css({'background':color, color: contrast(color), position:'absolute', top:0,left:0,textIndent:0})
           .appendTo(this);
     })