// Managing External Javascript and CSS files

var filesadded="" //list of files already added
var filedirectoryJs = "Files/System/DeltaQ_v2/scripts/";
var filedirectoryCss = "Files/System/DeltaQ_v2/css/";

function checkLoadedExtFile(filename, filetype) {
  if (filesadded.indexOf("["+filename+"]")==-1) {
    loadExtFile(filename, filetype);
    filesadded+="["+filename+"]";
  }
}

function removeExtFile(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 replaceExtFile(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=createExtFile2(newfilename, filetype);
         allsuspects[i].parentNode.replaceChild(newelement, allsuspects[i]);
      }
   }
}

// Support function for checkLoadedExtFile()
function loadExtFile(filename, filetype) {
   if (filetype=="js") {
      var fileref=document.createElement("script");
      fileref.setAttribute("type","text/javascript");
      fileref.setAttribute("src", filedirectoryJs + filename);
   }
   else if (filetype=="css") {
      var fileref=document.createElement("link")
      fileref.setAttribute("rel", "stylesheet");
      fileref.setAttribute("type", "text/css");
      fileref.setAttribute("href", filedirectoryCss + filename);
   }
   if (typeof fileref!="undefined")
      document.getElementsByTagName("head")[0].appendChild(fileref)
}

// Support function for replaceExtFile()
function createExtFile2(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", filedirectoryJs + 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", filedirectoryCss + filename)
   }
    return fileref;
}