IndigoHollow,
<!DOCTYPE HTML>
<html>
<head><meta charset="utf-8">
<title>Untitled</title>
</head>
<body> <table id="sf">
<tr>
<td>Бочка</td>
</tr>
<tr>
<td>Аквариум</td>
</tr>
<tr>
<td>Астронавт</td>
</tr>
<tr>
<td>Лопата</td>
</tr>
<tr>
<td>Аргентина</td>
</tr>
</table>
<input name="filt1" onclick="filtera('sf')" type="button" id="filt1" />
<script>
function filtera (_id1){
var table1 = document.getElementById(_id1);
var ele1;
for (var r = 1; r < table1.rows.length; r++) {
ele1 = table1.rows[r].innerHTML.replace(/<[^>]+>|\s/g,"");
var displayStyle = 'none';
if (ele1.toLowerCase().charAt(0) == 'а') displayStyle = '';
table1.rows[r].style.display = displayStyle;
}
}
</script>
</body>
</html>