qumo,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(function() {
$('.block_td').on('click', function(event){
var text = $.map($('span',this),function(el) {
return el.textContent
})
alert(text);
});
});
</script>
</head>
<body>
<table>
<tbody>
<tr>
<td class="block_td" ><span>первое</span> <span>второе</span></td>
</tr>
</tbody>
</table>
</body>
</html>