<html xmlns="http://www.w3.org/1999/xhtml">
<style>
#transformOriginDiv {
   position: absolute;
   width: 30px;
   height: 30px;
   background: green;
   transform: rotate(90deg);
}
</style>

<body>
  <div id="divRoot"></div>

  <script><![CDATA[

    function addTransformOriginDiv(x, y, transformOrigin)
    {
       var div = document.createElement("div");
       div.setAttribute("id", "transformOriginDiv");
       div.setAttribute("style", "top: " + y + "px; left: "+ x + "px; transform-origin: " + transformOrigin + ";");
       document.getElementById("divRoot").appendChild(div);
    }

    var equivalentTransformOrigins = [
         ["50% 50%", "center 50%", "50% center", "center", "center center"],
         ["0% 0%", "left 0%", "0% top", "left top", "top left"],
         ["0% 50%", "left 50%", "0% center", "left", "left center", "center left"],
         ["100% 0%", "right 0%", "100% top", "right top", "top right"],
         ["0% 50%", "left 50%", "0% center", "left center", "center left"],
         ["100% 50%", "right 50%", "100% center", "right center", "center right"],
         ["0% 100%", "left 100%", "0% bottom", "left bottom", "left bottom"],
         ["50% 100%", "center 100%", "50% bottom", "bottom", "center bottom", "bottom center"],
         ["100% 100%", "right 100%", "100% bottom", "right bottom", "bottom right"]
     ];

     for (var i = 0; i < equivalentTransformOrigins.length; i++)  {
         var x = 60 + (i %  4) * 60;
         var y = 60 + Math.floor(i / 4) * 60;
         equivalentTransformOrigins[i].map( function(s) { addTransformOriginDiv(x, y, s); } );
     }

  ]]></script>
</body>
</html>