重点——“:contains()”,文本过滤
<body>
<div><span>-</span><span class='count'>2</span><span>+</span></div>
<div>hello</div>
<div><span>101</span></div>
<button>click</button>
</body>
<script src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("button").click(function(){
var p = 101;
var n = $(':contains("'+p+'")').prev().prev().children("span.count").text();
n++;
$('span.count').html(n);
});
});
</script>