useful bookmarklet to toggle a 10px grid overlay on your page for design purposes

gridBookmarklet.js

(function(window, doc, undefined) {
  var awesomeGridBookmarkletElement = doc.getElementById('awesomeGridBookmarkletElement');
  if ( awesomeGridBookmarkletElement !== null) {
    awesomeGridBookmarkletElement.parentNode.removeChild(awesomeGridBookmarkletElement);
    return;
  } 
  var grid = doc.createElement('div');
  grid.id = 'awesomeGridBookmarkletElement';
  grid.style.backgroundImage = 'url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3AgUFTcrYHXFEgAAAAxpVFh0Q29tbWVudAAAAAAAvK6ymQAAABlJREFUGNNjZGBg+M9AJCBKIROxpo0qxAsADuYCECT/rwcAAAAASUVORK5CYII=)';
  grid.style.position = 'fixed';
  grid.style.top = 0;
  grid.style.left = 0;
  grid.style.height = '100%';
  grid.style.width = '100%';
  grid.style.opacity = 0.1;
  grid.style.pointerEvents = 'none';
  grid.style.zIndex = 9999999;
  doc.getElementsByTagName('body')[0].appendChild(grid);
})(window, document);

gridBookmarklet.min.js

javascript:(function(e,t,n){var r=t.getElementById("awesomeGridBookmarkletElement");if(r!==null){r.parentNode.removeChild(r);return}var i=t.createElement("div");i.id="awesomeGridBookmarkletElement",i.style.backgroundImage="url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3AgUFTcrYHXFEgAAAAxpVFh0Q29tbWVudAAAAAAAvK6ymQAAABlJREFUGNNjZGBg+M9AJCBKIROxpo0qxAsADuYCECT/rwcAAAAASUVORK5CYII=)",i.style.position="fixed",i.style.top=0,i.style.left=0,i.style.height="100%",i.style.width="100%",i.style.opacity=.1,i.style.pointerEvents="none",i.style.zIndex=9999999,t.getElementsByTagName("body")[0].appendChild(i)})(window,document)