Javascript regular expression: \B

<input type="button" value="Match1" onclick="javascript:demo('fred has a red car.');return false;" />
&nbsp;&nbsp;&nbsp;
<input type="button" value="Match2" onclick="javascript:demo('The rat is here.');return false;" />
&nbsp;&nbsp;&nbsp;
<input type="button" value="Match3" onclick="javascript:demo('100readers');return false;" />
&nbsp;&nbsp;&nbsp;
<input type="button" value="Match4" onclick="javascript:demo('_readers');return false;" />
<br /><br />
<input type="button" value="No Match1" onclick="javascript:demo('The price is\treduced.');return false;" />
&nbsp;&nbsp;&nbsp;
<input type="button" value="No Match2" onclick="javascript:demo('red is a color');return false;" />
&nbsp;&nbsp;&nbsp;
<input type="button" value="No Match3" onclick="javascript:demo('Action:\nread\nwrite');return false;" />
&nbsp;&nbsp;&nbsp;
<input type="button" value="No Match4" onclick="javascript:demo('Stop!read');return false;" />

<script type="text/javascript" language="JavaScript">
//<![CDATA[
   function demo(text) {
      var re = /\Bre/;
      if (text.match(re)) {
         alert("match");
      } else {
         alert("no match");
      }
   }
//]]>
</script>