code: function unescapeHtml(s) {
              if (_toString.call(s) != "[object String]") return s;
              if (!s) return "";
              return s.replace(/(&lt;)|(&gt;)|(&amp;)|(&quot;)/gm, function (match) {
                  switch (match) {
                      case "&lt;":
                          return "<";
                      case "&gt;":
                          return ">";
                      case "&amp;":
                          return "&";
                      case "&quot;":
                          return "\"";
                      default:
                          return match;
                  }
              });
          }
docs: HTML 문자열을 unescape 처리합니다.
  escapeHtml를 참고하세요.
  @method ax5.util.unescapeHtml
  @param {String} s
  @returns {string}
  @example
  ```
  ax5.util.unescapeHtml('HTML &lt;span&gt;string&lt;/span&gt; &amp; &quot;escape&quot;')
  //"HTML <span>string</span> & "escape""
  ```