function open_pop(which_url, which_window, win_width, win_height) {
  if (which_window === undefined) { which_window = 'vide_window'; }
  if (win_width === undefined) { win_width = '860'; }
  if (win_height === undefined) { win_height = '680'; }

	
  var win_spec = 'toolbar=0,location=0, directories=0, scrollbars=1, status=0, menubar=0, resizable=1, width=' + win_width + ', height=' + win_height;

  newwin = window.open(which_url, which_window, win_spec);
  window.self.name = "cfl_parent";
  newwin.focus();
}

function cfl_window(which_window, image_width, image_height) {
	var window_width = image_width + 46;
	var window_height = image_height + 175;
	newwin = window.open(which_window, "cfl_window",'toolbar=0,location=0,directories=0,scrollbars=1,status=0,menubar=0,resizable=1,width=' + window_width + ',height=' + window_height);
//	window.self.name = "cfl_parent";

	window.self.name = "cfl_parent_iframe";
	window.parent.name = "cfl_parent";
	//  movingwindow.focus();
}

function swf_window(which_window, image_width, image_height) {
	newwin = window.open(which_window, "cfl_window",'toolbar=0,location=0,directories=0,scrollbars=1,status=0,menubar=0,resizable=1,width=' + image_width + ',height=' + image_height);
//	window.self.name = "cfl_parent";
	window.self.name = "cfl_parent_iframe";
	window.parent.name = "cfl_parent";
	//  movingwindow.focus();
}

function send_to_friend(a_tag)
{ if (!a_tag) return true; window.open(a_tag.href, 'sendfriend', 'width=421,height=595,toolbar=0,location=0,status=0,menubar=0,scrollbars=0,resizable=1'); return false;}


// page manipulation js

function findimg()
{
 var imgs,i;
// Loop through all images, check if they contain the class roll
 imgs=document.getElementsByTagName('img');
 for(i=0;i<imgs.length;i++)
 {
  if(/roll/.test(imgs[i].className))
  {
// add the function roll to the parent Element of the image
  imgs[i].parentNode.onmouseover=function(){roll(this);};
  imgs[i].parentNode.onmouseout=function(){roll(this);};
  imgs[i].parentNode.onfocus=function(){roll(this);};
  imgs[i].parentNode.onblur=function(){roll(this);};
  }
 }
}
function roll(o)
{
 var i,isnode,src,ftype,newsrc,nownode;
// loop through all childNodes
 for (i=0;i<o.childNodes.length;i++)
 {
  nownode=o.childNodes[i];
// if the node is an element and an IMG set the variable and exit the loop
  if(nownode.nodeType==1 && /img/i.test(nownode.nodeName))
  {
   isnode=i;
   break;
  }
 }
// check src and do the rollover
 src = o.childNodes[isnode].src;
 ftype = src.substring(src.lastIndexOf('.'), src.length);
 if(/-on/.test(src))
 {
  newsrc = src.replace('-on','');
 }else{
  newsrc = src.replace(ftype, '-on'+ftype);
 }
 o.childNodes[isnode].src=newsrc;
}

function addScript(file){
 var newScript=document.createElement('script');
 newScript.src=file;
 document.body.appendChild(newScript);
}

window.onload=function(){
 findimg();

 // for adding a survey: please comment out when not in use
// addScript("/wgbh/nova/sciencenow/js/nsn-survey-global.js");
// addScript("/wgbh/nova/sciencenow/js/nsn-survey-survscript.js");
// addScript("/wgbh/nova/sciencenow/js/nsn-survey.js");
}