function showContent(tableID) {
var tbl = document.getElementById(tableID);
var rCount = tbl.rows.length;
try {
alert(tbl.rows[rCount - 1].cells[0].innerHTML);
} catch (e) {
alert(e);
}
}
<table border="1" id="dataTable">
<tr>
<td>
<Strong>Text</Strong>
</td>
<td>
<Strong>Font</Strong>
</td>
<td>
<Strong>Size</Strong>
</td>
<td>
<Strong>Color</Strong>
</td>
<tr>
<td>
<input type="Text">
</td>
<td>
<input type="Text">
</td>
<td>
<input type="Text">
</td>
<td>
<input type="Text">
</td>
</tr>
</tr>
</table>
<INPUT type="button" value="Add Row" onclick="addRow('dataTable')" />
<INPUT type="button" value="Delete Row" onclick="deleteRow('dataTable')" />
<INPUT type="button" value="Show" onclick="showContent('dataTable')" />