text: var cel =document.getElementById("cel");
  var fah = document.getElementById("fah");
  
  cel.addEventListener('input' ,function(){
  let c= this.value;
  let f= (c *9/5) +32;
  if(!Number.isInteger(f)){
      f=f.toFixed(4);
  }
  fah.value=f;
  });
  
  fah.addEventListener('input' , function(){
   let f= this.value;
   let c = (f - 32) * 5/9;
   if(!Number.isInteger(c)){
      c=c.toFixed(4);
  }
   cel.value=c;
  });
  