// Gets the text width.
TextWidth()
{
  const element = document.body;
  const propertyName = "font";
  const font = LJC.ElementStyle(element, propertyName);
  const text = "This is sample text.";
  const value = LJC.TextWidth(font, text);
  const result = LJC.Round(value);

  // With font = "16px "Times New Roman"
  // result:
  // 124
}