text: function getBorderRadiusValues(){
      var border = [];
  
      border[0] = document.getElementById('tl').value;
      border[1] = document.getElementById('tr').value;
      border[2] = document.getElementById('br').value;
      border[3] = document.getElementById('bl').value;
  
      for(let i = 0; i<4; i++){
          if(border[i] == '') border[i] = 0;
          else if(border[i] < 0) border[i] = 0;
          else if(border[i] > 50) border[i] = 50;
          else if(border[i] >= 0 && border[i] <= 50) continue;
      }
      return border[0] + '% ' + border[1] + '% ' + border[2] + '% ' +  border[3] + '%';                                                            
  }
  
  function tryBorderRadius(){
      document.getElementById('box').style.borderRadius = getBorderRadiusValues();                                                         
  }
  
  
  function copyBorderRadius() {
      var borderRadius = getBorderRadiusValues();
  
      console.log(borderRadius);
       
      copyStringToClipboard('border-radius: ' + borderRadius + ';');
  
      alert('COPY => border-radius: ' + borderRadius + ';');
  }
  
  function copyStringToClipboard (str) {
      var el = document.createElement('textarea');
      
      el.value = str;
      
      el.setAttribute('readonly', '');
      el.style = {position: 'absolute', left: '-9999px'};
      document.body.appendChild(el);
      
      el.select();
      
      document.execCommand('copy');
      
      document.body.removeChild(el);
  }
   