[code] Using Javascript to hide / unhide

init:function MarkSection () {
 if(document.getElementById('HideTarget')){
   /* Hide target */
   var HideTarget = document.getElementById('HideTarget');
   HideTarget.style.display = 'none';

   /* Add onclick function on trigger to hide or unhide target */
   var TriggerTarget = document.getElementById('TriggerTarget');
   TriggerTarget.onclick = function() {
     var HideTarget = document.getElementById('HideTarget');
     if (HideTarget.style.display == 'none') {
       HideTarget.style.display = 'block';
       this.style.backgroundImage = "url('TargetOn.gif')"
     } else {
       HideTarget.style.display = 'none';
       this.style.backgroundImage = "url('TargetOff.gif')"
     }
   } // end: onclick function
 } // end: if guidebody
} // end: function

addEvent(window, 'load', MarkSection.init)

function addEvent(obj, evType, fn){
 if (obj.addEventListener){
    obj.addEventListener(evType, fn, true);
    return true;
 } else if (obj.attachEvent){
    var r = obj.attachEvent("on"+evType, fn);
    return r;
 } else {
    return false;
 }
}

Reference: http://www.enterprisetrucks.com/include/faq.js