M@x,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
.hide{
display: none;
}
</style>
</head>
<body>
<table name="table">
<tbody>
<tr>
<td>1</td>
<td class="tempdat-1">test</td>
</tr>
<tr>
<td>1</td>
<td class="tempdat-2">test</td>
</tr>
<tr>
<td>1</td>
<td class="tempdat-3">test1</td>
</tr>
<tr>
<td>1</td>
<td class="tempdat-4">test1</td>
</tr>
<tr>
<td>1</td>
<td class="tempdat-5">test2</td>
</tr>
<tr>
<td>1</td>
<td class="tempdat-6">test1</td>
</tr>
<tr>
<td>1</td>
<td class="tempdat-7">test</td>
</tr>
<tr>
<td>1</td>
<td class="tempdat-8">test2</td>
</tr>
</tbody>
<!-- строк очень много-->
</table>
<script>
var uRows = {},
hiddenData = document.querySelectorAll("[class^='tempdat-']");
[].forEach.call(hiddenData, function(td) {
var numb = td.innerHTML;
if (!uRows[numb]) uRows[numb] = true;
else td.parentNode.classList.add("hide")
});
</script>
</body>
</html>