Problem with inserting JS code into Electron

I just started studying Electron just a couple of weeks ago and I had a problem, I'm trying to get my old works written in javascript and it just doesn't work, I don't know how to connect it correctly, yes, most likely it's easy, but for me As a beginner this is quite difficult. Thanks in advance for your time.

Index.html

<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="Content-Security-Policy" content="script-src 'self'"
    <title></title>
  </head>
  <body>
    Check
  </body>
  <script>require('chess.js') </script>
</html>

index.js

import { app, BrowserWindow } from 'electron';




if (require('electron-squirrel-startup') ){ 
  app.quit();
}

const chess = require('./chess')



let mainWindow;

const createWindow = () => {
  // Create the browser window.
  mainWindow = new BrowserWindow({
    width: 800,
    height: 600,
    minWidth: 500,
    minHeight: 200,
    icon: __dirname + "/icon.iso",
    webPreferences: { 
      nodeIntegration: false,
    },
  });
 


  mainWindow.loadURL(`file://${__dirname}/index.html`);




  mainWindow.on('closed', () => {

    mainWindow = null;
  });
};


app.on('ready', createWindow);

// Quit when all windows are closed.
app.on('window-all-closed', () => {
  // On OS X it is common for applications and their menu bar
  // to stay active until the user quits explicitly with Cmd + Q
  if (process.platform !== 'darwin') {
    app.quit();
  }
});

app.on('activate', () => {

  if (mainWindow === null) {
    createWindow();
  }
});

chess.js

pimg=new Array();
   i=new Array (
    "b",
    "bb1","bb2","bb3","bb4","bb5","bb6",
    "bw1","bw2","bw3","bw4","bw5","bw6",
    "l","r",
    "sbb1","sbb2","sbb3","sbb4","sbb5","sbb6",
    "sbw1","sbw2","sbw3","sbw4","sbw5","sbw6",
    "swb1","swb2","swb3","swb4","swb5","swb6",
    "sww1","sww2","sww3","sww4","sww5","sww6",
    "t","u","w",
    "wb1","wb2","wb3","wb4","wb5","wb6",
    "ww1","ww2","ww3","ww4","ww5","ww6"
   );
   for (j=0;j<i.length;++j) {
    pimg[j]=new Image();
    pimg[j].src=""+i[j]+".png";
   }
  
   N=1;
   K="";
   F=px=py=0;
  
   function sm(i) {
    if (N>120) return;
    var j="abcdefgh";
    if (N&1) { 
     if (N<19) K+=" ";
     K+=(1+N>>1)+". ";
    }
    else K+="   ";
    if (i.f==3) K+="o-o  ";
    else if(i.f==5) K+="o-o-o";
    else K+=j.charAt(i.x)+(8-i.y)+" "+j.charAt(i.X)+(8-i.Y);
    if (++N&1) K+="\n";
    document.getElementById("m"+Math.floor((N-2)/20)).innerHTML="<pre>"+K+"</pre>";
    if (!((N-1)%20)) K="";
   }
  
   function un(u,b) {
    for (var i=u.x.length-1;i>=0;--i) Z(b,u.x[i],u.y[i],u.p[i]);
   }
  
   function au(u,b,x,y) { 
    u.x.push(x); u.y.push(y); u.p.push(b[x+y*8]);
   }
  
   function st(x) {
    document.getElementById("i").innerHTML=x;
   }
   
   function P(x,y,X,Y,f) {
    this.x=x; this.y=y; this.X=X; this.Y=Y; this.f=f;
   }
  
   function U() { 
    this.x=[]; this.y=[]; this.p=[];
   }
  
   function em(b,x,y) {
    return !b[x+y*8];
   }
  
   function ge(b,x,y) {
    return b[x+y*8]&7;
   }
  
   function co(b,x,y) {
    return b[x+y*8]&192;
   }
  
   function sa(b,x,y,c) {
    var i=b[x+y*8]; return i&&(i&c);
   }
  
   function op(b,x,y,c){
    var i=b[x+y*8]; return i&&!(i&c);
   }
  
   function mo(b,x,y) {
    var i=b[x+y*8]; return i&&(i&32);
   }
   
   function la(b,x,y){
    var i=b[x+y*8]; return i&&(i&16);
   }
  
   function ra(x,y) {
    return x>=0&&x<8&&y>=0&&y<8;
   }
  
   function di(c) {
    return c==64?-1:1;
   }
  
   function Z(b,x,y,p) {
    b[x+y*8]=p; return b;
   }
   
   function t(b,x,y,i,j,c,l) {
    var X=x; var Y=y;
    while (ra(X+=i,Y+=j)&&em(b,X,Y)) l.push(new P(x,y,X,Y,0));
    if (ra(X,Y)&&op(b,X,Y,c)) l.push (new P(x,y,X,Y,0));
    return l;
   }
  
   function ro(b,x,y,c,l) {
    t(b,x,y,1,0,c,t(b,x,y,-1,0,c,t(b,x,y,0,1,c,t(b,x,y,0,-1,c,l))));
   }
  
   function bi(b,x,y,c,l) {
    t(b,x,y,1,1,c,t(b,x,y,-1,-1,c,t(b,x,y,1,-1,c,t(b,x,y,-1,1,c,l))));
   }
  
   function ki(b,x,y,c,l) {
    for(var i=-1;i<2;++i) 
    for(var j=-1;j<2;++j) {
     var X=x+i; var Y=y+j;
     if ((X||Y)&&ra(X,Y)&&!sa(b,X,Y,c)) l.push (new P(x,y,X,Y,0));
    }
    if (!mo(b,x,y)) if (em(b,5,y)&&em(b,6,y)&&!em(b,7,y)&&!mo(b,7,y)) {
     var u=new U();
     au(u,b,x,y);
     Z(b,x,y,0);
     var i=fi(b,c^192);
     var j=0; var X=-1;
     while (!j&&++X!=i.length) j=i[X].Y==y&&i[X].X==5;
     if(!j)l.push(new P(x,y,6,y,3));
     un(u,b);
    }
    else if(em(b,3,y)&&em(b,2,y)&&em(b,1,y)&&!em(b,0,y)&&!mo(b,0,y)) {
     var u=new U(); au(u,b,x,y); Z(b,x,y,0);
     var i=fi(b,c^192);
     var j=0; var X=-1;
     while (!j&&++X!=i.length) j=i[X].Y==y&&i[X].X==3;
     if (!j) l.push (new P(x,y,2,y,5));
     un(u,b);
    }
   }
   
   function kn(b,x,y,c,l) {
    for (var i=-2;i<3;++i)
    for (var j=-2;j<3;++j)
    if (Math.abs(i)+Math.abs(j)==3) {
     var X=x+i; var Y=y+j;
     if (ra(X,Y)&&!sa(b,X,Y,c)) l.push(new P(x,y,X,Y,0));
    }
   }
  
   function pa(b,x,y,c,l) {
    var Y=y+di(c); var Z=y+di(c)*2;
    if (!mo(b,x,y)&&em(b,x,Y)&&em(b,x,Z)) l.push(new P(x,y,x,Z,2));
    if (em(b,x,Y)) {
     if (!Y||Y==7) l.push(new P(x,y,x,Y,4));
     else l.push (new P(x,y,x,Y,0));
    }
    for (var i=-1;i<2;i+=2) {
     var X=x+i;if(ra(X,Y)) {
      if(op(b,X,Y,c)) {
       if (!Y||Y==7) l.push (new P(x,y,X,Y,4));
       else l.push (new P(x,y,X,Y,0));
      }
      else if (em(b,X,Y)&&la(b,X,Y-di(c))) l.push(new P(x,y,X,Y,1));
     }
    }
   }
  
   function d(b) {
    for (var y=0;y<8;++y)
    for(var x=0;x<8;++x) {
     var i="<img src=\"";
     if (F==1&&x==px&&y==py) i+="s"; i+=(x+y&1)?"b":"w";
     if (!em(b,x,y)) i+=(sa(b,x,y,64)?"w":"b")+(ge(b,x,y)&7);
     document.getElementById(""+x+y).innerHTML=i+".png\">";
    }
   }
  
   function ma(b,m) {
    u=new U();
    for (var x=0;x<8;++x)
    for (var y=0;y<8;++y)
    if (la(b,x,y)) {
     au(u,b,x,y); Z(b,x,y,ge(b,x,y)|co(b,x,y)|mo(b,x,y));
    }
    au(u,b,m.X,m.Y);
    if (m.f==4) Z(b,m.X,m.Y,37|co(b,m.x,m.y));
    else Z(b,m.X,m.Y,ge(b,m.x,m.y)|co(b,m.x,m.y)|32|(m.f==2?16:0));
    au(u,b,m.x,m.y);
    Z(b,m.x,m.y,0);
    if (m.f==1) { 
     au (u,b,m.X,m.Y-di(c));
     Z (b,m.X,m.Y-di(c),0);
    }
    else if(m.f==3) {
     au(u,b,5,m.y); au(u,b,7,m.y); Z(Z(b,5,m.y,ge(b,7,m.y)|co(b,7,m.y)|32),7,m.y,0);
    }
    else if(m.f==5) {
     au(u,b,3,m.y);au(u,b,0,m.y);Z(Z(b,3,m.y,ge(b,0,m.y)|co(b,0,m.y)|32),0,m.y,0);
    }
    return u;
   }
  
   function fi(b,c) { 
    var l=[];
    for (var x=0;x<8;++x)
    for (var y=0;y<8;++y)
    if (sa(b,x,y,c)) {
     var i=ge(b,x,y);
     if (i==1) pa(b,x,y,c,l);
     else if(i==2) kn(b,x,y,c,l);
     else if(i==3) bi(b,x,y,c,l);
     else if(i==4) ro(b,x,y,c,l);
     else if(i==5) {
      bi(b,x,y,c,l); ro(b,x,y,c,l)
     }
     else if(i==6) ki(b,x,y,c,l);
    }
    for (var i=0;i<l.length/3;++i) {
     var j=Math.floor(Math.random()*l.length);
     var k=Math.floor(Math.random()*l.length);
     var x=l[j];l[j]=l[k];l[k]=x;
    }
    return l;
   }
  
   var Sp=[0,60,370,370,450,1000,5000];
   var Sb=[
    [0,0,0,0,0,0,0,0,2,3,4,0,0,4,3,2,4,6,12,12,12,4,6,4,4,7,18,25,25,16,7,4,6,11,
    18,27,27,16,11,6,10,15,24,32,32,24,15,10,10,15,24,32,32,24,15,10,0,0,0,0,0,0,0,0],
    [-7,-3,1,3,3,1,-3,-7,2,6,14,20,20,14,6,2,6,14,22,26,26,22,14,6,8,18,26,30,30,26,18,
    8,8,18,30,32,32,30,18,8,6,14,28,32,32,28,14,6,2,6,14,20,20,14,6,2,-7,-3,1,3,3,1,-3,-7],
    [16,16,16,16,16,16,16,16,26,29,31,31,31,31,29,26,26,28,32,32,32,32,28,26,16,26,32,32,32,
    32,26,16,16,26,32,32,32,32,26,16,16,28,32,32,32,32,28,16,16,29,31,31,31,31,29,16,16,16,16,16,16,16,16,16],
    [0,0,0,3,3,0,0,0,-2,0,0,0,0,0,0,-2,-2,0,0,0,0,0,0,-2,-2,0,0,0,0,0,0,-2,-2,0,0,0,0,0,0,-2,
    -2,0,0,0,0,0,0,-2,10,10,10,10,10,10,10,10,0,0,0,0,0,0,0,0],
    [-2,-2,-2,0,0,-2,-2,-2,0,0,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,0,0,
    2,2,0,0,0,0,0,0,2,2,0,0,0,-2,-2,0,0,0,0,0,0,-2,-2,0,0,0,0,0,0,-2,-2,0,0,0,0,0,0],
    [3,3,8,-12,-8,-12,10,5,0,0,-5,-5,-12,-12,-12,-12,-5,-5,-7,-15,-15,-15,-15,-15,-15,
    -7,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,
    -20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20,-20],[]];
   for (var x=0;x<8;++x)
   for(var y=0;y<8;++y) Sb[6][x+y*8]=Sb[5][(7-x)+y*8];
  
   function sc(b,c) {
    var s=0;
    for (var x=0;x<8;++x)
    for(var y=0;y<8;++y) {
     var i=ge(b,x,y);
     if (i) if (sa(b,x,y,128)) s+=Sb[i==6?6:i-1][(7-x)+y*8]+Sp[i];
     else s-=Sb[i-1][x+(7-y)*8]+Sp[i];
    }
    return c==128?s:-s;
   }
  
   function cpu() {
    if(F!=2) return;
    var now = new Date();
    var m=fi(b,c); var bs=-99999; var ws=bs; var bm=0; var C=c^192; var kx=0; var ky=0;
    for (var i=0;i<m.length;++i) {
     var u=ma(b,m[i]);
     if (ge(b,kx,ky)!=6||sa(b,kx,ky,C)) {
      kx=ky=0;
      while (ge(b,kx,ky)!=6||sa(b,kx,ky,C)) if (++kx==8) { kx=0; ++ky; }
     }
     var om=fi(b,C); var obs=-99999; var ows=99999;
     for (var j=0;j<om.length;++j) {
      if (kx==om[j].X&&ky==om[j].Y) {
       obs=-99999; break;
      }
      var U=ma(b,om[j]); var r=sc(b,c);
      un(U,b); obs=Math.max(obs,r); ows=Math.min(ows,r);
      if (r<ws) break;
     }
     un(u,b);
     if (obs>bs&&ows>ws) {
      bs=obs; ws=ows; bm=m[i];
     }
    }
    ma(b,bm); sm(bm); nx(); st("����� �� ��� "+(new Date()-now)/1000+" ���.");
   }
  
   cpw=0; cpb=1;
  
   function pw(e) {
    cpw=e.checked;
    if (F<2&&cpw&&c==64) {
     F=2; setTimeout("cpu()",100);
    }
   }
  
   function pb(e) {
    cpb=e.checked;
    if (F<2&&cpb&&c==128) {
     F=2; setTimeout("cpu()",100);
    }
   }
  
   function l() { 
    b=[];
    for (i=0;i<8;++i) Z(Z(b,i,6,65),i,1,129);
    d(Z(Z(Z(Z(Z(Z(Z(Z(Z(Z(Z(Z(Z(Z(Z(Z(b,0,0,132),1,0,130),2,0,131),3,0,133),4,0,134),
     5,0,131),6,0,130),7,0,132),0,7,68),1,7,66),2,7,67),3,7,69),4,7,70),5,7,67),6,7,66),7,7,68));
    c=64;
   }
  
   function hu(x,y) { 
    if (F==0) {
     if (sa(b,x,y,c)) {
      px=x; py=y; F=1; d(b);
     }
    }
    else if(F==1) {
     if (x==px&&y==py) {
      F=0; d(b); return;
     }
     var m=fi(b,c);
     for (var i=0;i<m.length;++i) { 
      if (m[i].x==px&&m[i].y==py&&m[i].X==x&&m[i].Y==y&&ge(b,x,y)!=6) {
       var u=ma(b,m[i]); var o=fi(b,c^192);
       for (var j=0;j<o.length;++j) if (ge(b,o[j].X,o[j].Y)==6&&sa(b,o[j].X,o[j].Y,c)) {
        un(u,b); st("�������� ���!"); return;
       }
       sm(m[i]); nx(); return;
      }
     }
     st("�������� ���!");
    }
   }
  
   function nx() {
    c^=192; F=0; d(b);
    for (var x=0;x<8;++x)
    for (var y=0;y<8;++y)
    if (ge(b,x,y)==6 && sa(b,x,y,c)) {
     var kx=x; var ky=y;
    }
    var m=fi(b,c^192); var ic=0;
    for (var i=0;i<m.length;++i) if(m[i].X==kx&&m[i].Y==ky) ic=1;
    var m=fi(b,c); var cm=1;
    for (var i=0;i<m.length;++i) {
     var u=ma(b,m[i]);
     for (var x=0;x<8;++x) 
     for(var y=0;y<8;++y) 
     if (ge(b,x,y)==6&&sa(b,x,y,c)) {
      var kx=x; var ky=y;
     }
     var om=fi(b,c^192); un(u,b); var hm=0;
     for (var j=0;j<om.length;++j) if (om[j].X==kx&&om[j].Y==ky) hm=1; cm&=hm;
    }
    if (cm) {
     alert(ic?"���!":"���!"); F=3; return;
    }
    if ((cpw&&c==64)||(cpb&&c==128)) {
     F=2; setTimeout("cpu()",500);
    }
   }
  
  
  // SecondOne__-----------------------------------------------------------------------
  
   for (var i=0;i<8;++i) {
   document.write("<img src=\"l.png\">");
   for (var j=0;j<8;++j) document.write("<span onclick=\"hu("+j+","+i+")\" id=\""+j+i+"\"><img></span>");
   document.write("<img src=\"r.png\"><br>");
  }