code: private static String filenameValue(String nameEqualsValue) {
          int idx = nameEqualsValue.indexOf('=');
          String value = nameEqualsValue.substring(idx + 1).trim();
  
          if (value.matches(".??[a-z,A-Z]\\:\\\\[^\\\\].*")) {
              // incorrectly escaped IE filenames that have the whole path
              // we just strip any leading & trailing quotes and leave it as is
              char first = value.charAt(0);
              if (first == '"' || first == '\'')
                  value = value.substring(1);
              char last = value.charAt(value.length() - 1);
              if (last == '"' || last == '\'')
                  value = value.substring(0, value.length() - 1);
  
              return value;
          } else
              // unquote the string, but allow any backslashes that don't
              // form a valid escape sequence to remain as many browsers
              // even on *nix systems will not escape a filename containing
              // backslashes
              return QuotedStringTokenizer.unquoteOnly(value, true);
      }
docs: /* ------------------------------------------------------------