<p id="P_MY_HEADER"></p>

<p>#TOTAL_ROWS#</p>
<script type="text/javascript">
  function setMyHeader(){document.getElementById('P_MY_HEADER').innerHTML = #TOTAL_ROWS#;
  }
 // or a more generic version would be
  function displayValue(id){    
    alert('The Value is ' + document.getElementById(id).value );
  }

 setMyHeader();
</script>

<p id="P_MY_HEADER"></p>

<p>#TOTAL_ROWS#</p>
<script type="text/javascript">
  function setMyHeader(){document.getElementById('P_MY_HEADER').innerHTML = #TOTAL_ROWS#;
  }

 setMyHeader();
</script>