function loadjscssfile(filename, filetype)
{
  if (filetype=="js")
  { //if filename is a external JavaScript file
    var fileref=document.createElement('script')
    fileref.setAttribute("type","text/javascript")
    fileref.setAttribute("src", filename)
  }
  else
  if (filetype=="css")
  { //if filename is an external CSS file
    var fileref=document.createElement("link")
    fileref.setAttribute("rel", "stylesheet")
    fileref.setAttribute("type", "text/css")
    fileref.setAttribute("href", filename)
  }
  if (typeof fileref!="undefined")
    document.getElementsByTagName("head")[0].appendChild(fileref)
}

function checkloadjscssfile(filename, filetype)
{
  var filesadded="" //list of files already added
  if (filesadded.indexOf("["+filename+"]")==-1)
  {
    loadjscssfile(filename, filetype)
    filesadded+="["+filename+"]" //List of files added in the form "[filename1],[filename2],etc"
  }
  else
    alert("file already added!")
}

function createjscssfile(filename, filetype)
{
  if (filetype=="js")
  { //if filename is a external JavaScript file
    var fileref=document.createElement('script')
    fileref.setAttribute("type","text/javascript")
    fileref.setAttribute("src", filename)
  }
  else
  if (filetype=="css")
  { //if filename is an external CSS file
    var fileref=document.createElement("link")
    fileref.setAttribute("rel", "stylesheet")
    fileref.setAttribute("type", "text/css")
    fileref.setAttribute("href", filename)
  }
  return fileref
}

function removejscssfile(filename, filetype)
{
  var targetelement=(filetype=="js")? "script" : (filetype=="css")? "link" : "none" //determine element type to create nodelist from
  var targetattr=(filetype=="js")? "src" : (filetype=="css")? "href" : "none" //determine corresponding attribute to test for
  var allsuspects=document.getElementsByTagName(targetelement)
  for (var i=allsuspects.length; i>=0; i--)
  { //search backwards within nodelist for matching elements to remove
    if (allsuspects[i] && allsuspects[i].getAttribute(targetattr)!=null && allsuspects[i].getAttribute(targetattr).indexOf(filename)!=-1)
      allsuspects[i].parentNode.removeChild(allsuspects[i]) //remove element by calling parentNode.removeChild()
  }
}

function replacejscssfile(oldfilename, newfilename, filetype)
{
  var targetelement=(filetype=="js")? "script" : (filetype=="css")? "link" : "none" //determine element type to create nodelist using
  var targetattr=(filetype=="js")? "src" : (filetype=="css")? "href" : "none" //determine corresponding attribute to test for
  var allsuspects=document.getElementsByTagName(targetelement)
  for (var i=allsuspects.length; i>=0; i--)
  { //search backwards within nodelist for matching elements to remove
    if (allsuspects[i] && allsuspects[i].getAttribute(targetattr)!=null && allsuspects[i].getAttribute(targetattr).indexOf(oldfilename)!=-1)
    {
      var newelement=createjscssfile(newfilename, filetype)
      allsuspects[i].parentNode.replaceChild(newelement, allsuspects[i])
    }
  }
}