$(document).ready(function(){
 var whiteRoundedCornerSpans = '<span class="corner whitetl tl">&nbsp;</span><span class="corner whitebr br">&nbsp;</span><span class="corner whitebl bl">&nbsp;</span><span class="corner whitetr tr">&nbsp;</span>';
 $("#main").append(whiteRoundedCornerSpans);


 var lightBlueRoundedCornerSpans = '<span class="corner darkbluetl tl">&nbsp;</span><span class="corner lightbluebr br">&nbsp;</span><span class="corner lightbluebl bl">&nbsp;</span><span class="corner darkbluetr tr">&nbsp;</span>';
 $(".lightBlueCornersContainer").append(lightBlueRoundedCornerSpans);
});