</code> is a valid index for <code>buffer</code>.
 <p>
 The matching code may check one character or many.
 It may check characters preceding <code>pos</code> as well as those after.
 <p>
 It must return zero for no match, or a positive number if a match was found.
 The number indicates the number of characters that matched.</div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>buffer</code> - the text content to match against, do not change</dd><dd><code>pos</code> - the starting position for