Considere a página HTML abaixo, contida na mesma pasta da biblioteca jquery-2.1.4.min:
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="jquery-2.1.4.min">
</script>
<script type="text/javascript">
$(document).ready(function() {
$('button').click(function() {
$('..I.... ').css('background', 'red');
});
});
</script>
</head>
<body>
<button type="button">Aplicar</button>
<table border="1">
<tr><td>A</td></tr>
<tr><td>B</td></tr>
<tr><td>C</td></tr>
<tr><td>D</td></tr>
</table>
</body>
</html>