phonegap的navigator.app.exitApp()失效

原始內容如下:
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<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
<meta name="format-detection" content="telephone=no" />
        <meta name="msapplication-tap-highlight" content="no" />
        <!-- WARNING: for iOS 7, remove the width=device-width and height=device-height attributes. See https://issues.apache.org/jira/browse/CB-4323 -->
        <meta name="viewport" content="user-scalable=no, initial-scale=1, maximum-scale=1, minimum-scale=1, width=device-width, height=device-height, target-densitydpi=medium-dpi" />
        <link rel="stylesheet" type="text/css" href="css/jquery.mobile-1.4.5.min.css" />
        <title>Exit Testing</title>
    </head>
    <body>
   <section data-role="page" id="pg1">
<a id="a_exit" href="#" class="ui-btn ui-btn-inline">離開</a>
</section> <!-- page pg1 -->
</body>
</html>

<script type="text/javascript" src="jquery-2.1.1.min.js"></script>
<script type="text/javascript" src="jquery.mobile-1.4.5.min.js"></script>

<script>
     // Wait for device API libraries to load
    document.addEventListener("deviceready", onDeviceReady, false);

    // device APIs are available
    function onDeviceReady() {
        //Exit APP
$("#a_exit").on("tap",function(){
            navigator.app.exitApp();
});
    }
</script>

以Phonegap編譯成APP後,實地測試的結果失敗,無法正確關閉APP。
原因是找不到navigator.app.exitApp()這個函數,因為沒有把js掛進來。
加上下列的語法,重新編譯後就可以正常離開了。
<script type="text/javascript" src="cordova.js"></script>