text: function chessboard(n) {
      let html = '<div class="chessboard">\n';
      let color = 'black';
      for (let row = 1; row <= n; row++){
          html += "  <div>\n";
          for (let col = 0; col <= n; col++) {
              html += `    <span class="${color}"></span>\n`;
              if(color == "white")
                  color = "black";
              else
                  color = "white";
          }
          html += "  </div>\n";        
      }
  
      html += "</div>\n";
      if(n % 2 == 0)
              if(color == "white")
                  color = "black";
              else
                  color = "white";
      return html;
  }
  
  