$("button").click(function () {
var str = $(this).text();
$("tr").css("background", "white");
$("tr" + str).css("background", "#ff0000");
$("#inner").text(str);
});
<html>
<head>
<script src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
</head>
<body>
<div>
<button>:nth-child(even)</button>
<button>:nth-child(odd)</button>
<button>:nth-child(3n)</button>
<button>:nth-child(2)</button>
<button>:eq(2)</button>
<button>:eq(5)</button>
</div>
<div>
<button>:nth-child(3n+1)</button>
<button>:nth-child(3n+2)</button>
<button>:even</button>
<button>:odd</button>
</div>
<div>
<table>
<tr><td>JQuery</td></tr>
<tr><td>Karl</td></tr>
<tr><td>Brandon</td></tr>
<tr><td>Benjamin</td></tr>
</table>
</div>
<div>
<table>
<tr><td>Sam</td></tr>
</table>
</div>
<div>
<table>
<tr><td>Glen</td></tr>
<tr><td>Tane</td></tr>
<tr><td>Ralph</td></tr>
<tr><td>David</td></tr>
<tr><td>Mike</td></tr>
<tr><td>Dan</td></tr>
</table>
</div>
<span>
tr
<span id="inner"></span>
</span>
</body>
</html>
button { display:block; font-size:12px; width:100px; }
div {
float:left; margin:10px; font-size:12px;
border:1px solid black;
}
span { color:blue; font-size:18px; }
#inner { color:red; }
td { width:50px; text-align:center; }