function changefont(fontclass) {
      content = document.getElementById('documentcontent');

      if (fontclass == 'arial') {
            content.style.fontFamily = 'Arial';
            content.style.fontSize = '12px';
      } else if (fontclass== 'times') {
            content.style.fontFamily = 'Times New Roman';
            content.style.fontSize = '15px';
      } else if (fontclass== 'verdana') {
            content.style.fontFamily = 'Verdana';
            content.style.fontSize = '12px';
      }
}