tinycore linux firefox file upload crash workaround improved

/*
put this portion inside a bookmark in Firefox with "javascript:" protocol prefix

this script depends on 2 of my other scripts:
 node_insec_basic_wup.js  (a simple nodejs server)
 and fuwp.html, a file that uses the server to request uploads
 you can find both of these in my public pastes https://pastebin.com/u/IWBH_01
*/
self.firdy=new WeakMap(); //file input ready

HTMLInputElement.prototype.__defineGetter__("files",
function(){ if(firdy.has(this))return firdy.get(this); }
);

var itemF=function item(i){ return this[i]; };
FileList.prototype.__defineGetter__("item",function(){ return itemF; });


self._w2_=self.open("http://127.0.0.1:120/*fuwp.html?or="+btoa(self.origin));



//opening file browse box
var FnavBox=document.createElement("div"),
FBs=FnavBox.style;
FBs.backgroundColor="white";
FBs.position="fixed";
FBs.top="50px";
FBs.left="50px";
FBs.width="400px";
FBs.height="300px";
FBs.border="2px solid gray";
FBs.zIndex="999999";

var fiBx2=document.createElement("div"),
f2s=fiBx2.style;
f2s.overflow="scroll";
f2s.border="2px solid grey";
f2s.width="350px";
f2s.height="200px";
fiBx2.onclick=function(e){
 var tar=e.target||e.srcElement;
 if(tar.nodeName=="BUTTON"){
  pthD.value+=tar.innerText;
  if(tar.parentNode.parentNode.children[1].innerText=="Folder"){pthD.value+="/";
   _w2_.postMessage({"nav":!0,"do":pthD.value},"http://127.0.0.1:120");
  }
 }
};
FnavBox.appendChild(fiBx2);

var pthD=document.createElement("input");
pthD.type="text";
FnavBox.appendChild(pthD);

var opnB=document.createElement("button");
opnB.innerText="Open";
opnB.onclick=function(){
 if(pthD.value){ //if path selected
  var o2={"do":pthD.value};
  if(o2.do[o2.do.length-1]=="/"){
   o2.nav=!0;
  }else{ //if path is not dir
   o2.l0d=!0;
  }
  _w2_.postMessage(o2,"http://127.0.0.1:120");
 }
};
FnavBox.appendChild(opnB);

var clsB=document.createElement("button");
clsB.innerText="Cancel";
clsB.onclick=function(){
 document.body.removeChild(FnavBox);
 pthD.value="";
 fiBx2.innerHTML="";
};
FnavBox.appendChild(clsB);




self.addEventListener("click",self.fuhf_=function(e){
 var tar=e.target||e.srcElement;
 if(tar.nodeName=="INPUT"&&tar.type=="file"){
  e.preventDefault();

  self.curAinp=tar;

  document.body.appendChild(FnavBox);
  _w2_.postMessage({"nav":!0,"do":"/"},"http://127.0.0.1:120");
 }
});

self.addEventListener("message",function(e){
 self._LM_=e;
 if(e.source==_w2_){
  var da=e.data;
  if(da.dir){
   //render dir
   var i=0,fc=da.dir,L=fc.length,ci,rH="<table><tbody>";
   while(i<L){
    ci=fc[i];
    rH+="<tr><td><button>"+ci[0]+"</button></td><td>"+ci.slice(1).join("</td><td>")+"</td></tr>";
    i++;
   }
   fiBx2.innerHTML=rH+"</tbody></table>";
  }else if(da.files){
   //upload files
   var i=0,files=[],Lifs=da.files,L=Lifs.length,cf;
   while(i<L){ cf=Lifs[i]; files.push(new File([cf[0]],cf[1],{"type":cf[2]})); i++;}

   files.__proto__=FileList.prototype;
   firdy.set(curAinp,files);

   var ae=new Event("change");

   curAinp.dispatchEvent(ae);
  }
 }
});


//end main page side script