petral7,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<table width="400" summary="" >
<tbody>
<tr>
<td class="header_cell" style="color: rgb(170, 98, 198);">
<b>Дата:</b>
08-июл-1982
</td>
</tr>
</tbody>
</table>
<script>
var td = document.querySelector(".header_cell"),
text = td.lastChild.textContent.trim();
alert(text)
</script>
</body>
</html>