Mirtle@tut.by,
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<script src="http://code.jquery.com/jquery-1.11.3.min.js"></script>
<style>
li{list-style: none; background-color: #DEB887;border : 1px solid #FF0000; width: 200px;}
label{
display: block;
width: 100%;
}
</style>
</head>
<body>
<div>
<h2>Таблица</h2>
<ul>
<li><label><input type = "checkbox"> кот </label></li>
<li><label><input type = "checkbox"> собака </label></li>
</ul>
<form>
<input type = "text">
<input type = "submit">
</form>
</div>
<script>
var inp = $("input:text");
$("div").on("click", "input:submit, input:checkbox", function(a) {
$(this).is(":checkbox") ? $(this).parents("li").css("text-decoration", this.checked ? "line-through" : "none") :
(a.preventDefault(), (a = $.trim(inp.val())) && $("<li><label><input type = 'checkbox'> " + a + " </label></li>").appendTo("ul"), inp.val(""))
});
</script>
</body>
</html>