This may help you using css:
PHP Code:
<html>
<head>
<style type="text/css">
table.thinBorder {
border-collapse: collapse;
}
table.thinBorder, table.thinBorder tr td {
border: 1px solid #000000;
}
</style>
</head>
<body>
<table class="thinBorder" border="0">
<tr>
<td>1</td>
<td>2</td>
<td>3</td>
</tr>
<tr>
<td>4</td>
<td>5</td>
<td>6</td>
</tr>
</table>
</body>
</html>
hope this helps