[bes]

так получше будет

<style>
	td {
		border: solid 1px;
	}
</style>

<table>
	<tr id="a00">
		<td>11</td>
		<td>12</td>
	</tr>
	<tr id="a01">
		<td>21</td>
		<td>22</td>
	</tr>
	<tr id="a02">
		<td>31</td>
		<td>32</td>
	</tr>
	<tr id="a03">
		<td>41</td>
		<td>42</td>
	</tr>
	<tr id="a04">
		<td>51</td>
		<td>52</td>
	</tr>
</table>
<button>hide</button>
<button>show</button>

<script>
window.onload = function () {
	var elems = document.body.children;
	var rows = elems[0].rows;
	var len = rows.length;
	
	for (var i = 0; i < len; i++) {
		rows[i].style.display = 'block';
	}
	
	function sh(first, last, mode) {
		if (last < len) {
			if (last == first) {
				var l = last + 1;
			} else 
			if (last > first) {
				var l = last + 1;
			}
		} else {
			return;
		}
		
		var disp;
		(mode == 'hide') ? disp = 'none': disp = 'block';
		
		for (var i = first; i < l; i++) {
			if (rows[i].style.display != disp) {
				rows[i].style.display = disp;
			}
		}
	}
	
	elems[1].onclick = function () {
		var first = Number(prompt('first', 1));
		var last = Number(prompt('last', 2));
		sh(first, last, 'hide');
	}
	elems[2].onclick = function () {
		var first = Number(prompt('first', 1));
		var last = Number(prompt('last', 2));
		sh(first, last, 'show');
	}
}
</script>