gistfile1.js

var  timeout_setter=0;

var hideExpandableClassElements = function (){
  var allPageTags=document.getElementsByTagName("*"); 
   //Cycle through the tags using a for loop 
   for (i=0; i<allPageTags.length; i++) { 
   //Pick out the tags with our class name 
      if (allPageTags[i].className=="entry-content notfirst") { 
   //Manipulate this in whatever way you want 
      allPageTags[i].style.display='none'; 
      } 
   }
} 
function ttt(element){
   $('content_'+element.id).show();
   clearTimeout(timeout_setter);
  }
  
var aaa = function(element){
  timeout_setter= setTimeout("hideExpandableClassElements()" ,300);
}

window.onload = function() {
 // Find all elements that use that given CSS class
 $$('.expandable').each(function(e) {
   
   e.observe('mouseover', ttt.curry(e));
   e.observe('mouseout',aaa);
 });
 

}