text: const span = document.querySelector('span')
  const btnStart = document.querySelector('#btnStart')
  const btnPause = document.querySelector('#btnPause')
  const btnClean = document.querySelector('#btnClean')
  
  var interval 
  
  btnStart.onclick = ()=>{
      btnStart.disabled = true
      btnPause.disabled = false
  
      var value = parseFloat(span.innerHTML)
      
      interval = setInterval(()=>{
          value += 0.1
      
          span.innerHTML = value.toFixed(1)
      },100);
  }
  //======================================================================
  btnPause.onclick = ()=>{
      btnStart.disabled = false
      btnPause.disabled = true
  
      clearInterval(interval)
  }
  
      btnClean.onclick = ()=>{
      btnStart.disabled = false
      btnPause.disabled = true
  
      clearInterval(interval)
      span.innerHTML = "0.0"
  }