使用粗体显示字符串 - 在线编辑器

          <script>
  var txt = "Hello World!";
  document.write("<p>字体变大: " + txt.big() + "</p>");
  document.write("<p>字体缩小: " + txt.small() + "</p>");
  document.write("<p>字体加粗: " + txt.bold() + "</p>");
  document.write("<p>斜体: " + txt.italics() + "</p>");
  document.write("<p>固定定位: " + txt.fixed() + "</p>");
  document.write("<p>加删除线: " + txt.strike() + "</p>");
  document.write("<p>字体颜色: " + txt.fontcolor("green") + "</p>");
  document.write("<p>字体大小: " + txt.fontsize(6) + "</p>");
  document.write("<p>下标: " + txt.sub() + "</p>");
  document.write("<p>上标: " + txt.sup() + "</p>");
  document.write("<p>链接: " + txt.link("https://www.mifengjc.com") + "</p>");
  document.write("<p>闪动文本: " + txt.blink() + " (不能用于IE,Chrome,或者Safari)</p>");
</script>
        