找出单击了哪个弹出按钮

Question

给出以下示例

<div data-role="popup" id="popupDialog" data-overlay-theme="b" data-theme="b" data-dismissible="false" style="max-width:400px;">
<div data-role="header" data-theme="a">
<h1>Delete Page?</h1>
</div>
<div role="main" class="ui-content">
    <h3 class="ui-title">Are you sure you want to delete this page?</h3>
<p>This action cannot be undone.</p>
    <a href="#" class="ui-btn ui-corner-all ui-shadow ui-btn-inline ui-btn-b" data-rel="back">Cancel</a>
    <a href="#" class="ui-btn ui-corner-all ui-shadow ui-btn-inline ui-btn-b" data-rel="back" data-transition="flow">Delete now</a>
    <a href="#" class="ui-btn ui-corner-all ui-shadow ui-btn-inline ui-btn-b" data-rel="back" data-transition="flow">delete it tomorrow</a>
    <a href="#" class="ui-btn ui-corner-all ui-shadow ui-btn-inline ui-btn-b" data-rel="back" data-transition="flow">delete it next week</a>
</div>

然后用以下javascript代码打开对话框

$("#popupDialog").popup("open");

有人可以告诉我如何判断点击了哪个按钮？