function init() {
     brow = "new";
     if (navigator.appName == "Netscape" && navigator.appVersion.charAt(0) < 5) { brow = "old";
//alert( navigator.appName + " " + navigator.appVersion.charAt(0) + " is old");
       } else { 
//alert( navigator.appName + " " + navigator.appVersion.charAt(0) + " is new" );
       }  

     if (navigator.appName != "Netscape" && navigator.appName != "Microsoft Internet Explorer") { 
 alert("This browser may be site-incompatible."); }

     if ( brow == "old" ) {
       this.nDIV = eval("document" + ".noyauDiv");
       this.e1DIV = eval("document" + ".electron1Div");
       this.e2DIV = eval("document" + ".electron2Div");
       this.e3DIV = eval("document" + ".electron3Div");
     }

  r3 = 180;
  r2 =  80;
  r1 =  20;
  phi1 = 0;
  phi2 = 0;
  phi3 = 0;
  dp3 = 1.481;
  dp2 = 5;
  dp1 = 40;
  width = 30;
  height=30;

     if (brow == "old") {
       noyauX = parseInt(this.nDIV.left) + 5;
       noyauY = parseInt(this.nDIV.top) + 12;
     } else {
       noyauX = parseInt(document.getElementById('noyauDiv').style.left) + 5;
       noyauY = parseInt(document.getElementById('noyauDiv').style.top) + 12;
     }
       if ( brow == "new" ) {
         electron1X = parseInt(document.getElementById('electron1Div').style.left);
         electron1Y = parseInt(document.getElementById('electron1Div').style.top);
         electron2X = parseInt(document.getElementById('electron2Div').style.left);
         electron2Y = parseInt(document.getElementById('electron2Div').style.top);
         electron3X = parseInt(document.getElementById('electron3Div').style.left);
         electron3Y = parseInt(document.getElementById('electron3Div').style.top);
       } else { 
         electron1X = parseInt(this.e1DIV.left);
         electron1Y = parseInt(this.e1DIV.top);
         electron2X = parseInt(this.e2DIV.left);
         electron2Y = parseInt(this.e2DIV.top);
         electron3X = parseInt(this.e3DIV.left);
         electron3Y = parseInt(this.e3DIV.top);
       }
  plotElectrons();
}
function plotElectrons() {
     if ( brow == "old" ) {
       this.e1DIV.left = noyauX + r1*Math.cos(phi1*Math.PI/180) - width/2;
       this.e1DIV.top  = noyauY - r1*Math.sin(phi1*Math.PI/180) - height/2;
       this.e2DIV.left = noyauX + r2*Math.cos(phi2*Math.PI/180) - width/2;
       this.e2DIV.top  = noyauY - r2*Math.sin(phi2*Math.PI/180) - height/2;
       this.e3DIV.left = noyauX + r3*Math.cos(phi3*Math.PI/180) - width/2;
       this.e3DIV.top  = noyauY - r3*Math.sin(phi3*Math.PI/180) - height/2;
     } else {
       document.getElementById('electron1Div').style.left = noyauX + r1*Math.cos(phi1*Math.PI/180) - width/2;
       document.getElementById('electron1Div').style.top = noyauY - r1*Math.sin(phi1*Math.PI/180) - height/2;
       document.getElementById('electron2Div').style.left = noyauX + r2*Math.cos(phi2*Math.PI/180) - width/2;
       document.getElementById('electron2Div').style.top = noyauY - r2*Math.sin(phi2*Math.PI/180) - height/2;
       document.getElementById('electron3Div').style.left = noyauX + r3*Math.cos(phi3*Math.PI/180) - width/2;
       document.getElementById('electron3Div').style.top = noyauY - r3*Math.sin(phi3*Math.PI/180) - height/2;
     }

//  setup next point
  phi1 += dp1;
  phi2 += dp2;
  phi3 += dp3;
  timerID = setTimeout("plotElectrons()",80);
}

function stopclock() {
  if (timerID ) clearTimeout(timerID);
}