text: function clicar(){
   let num = document.querySelector('#txtn1')
   let sel = document.querySelector('#tabuada')
  
   if (num.value.length == 0){
      window.alert('Por favor, digite um numero')
  }else{
   let n = Number(num.value)
   let c = 1
   sel.innerHTML= ''
   while (c <= 10){
      let item = document.createElement('option')
      item.text = `${n} x ${c} = ${n * c}`
      sel.appendChild(item)
      c++
  
   }
          
     
   }
  }