span>&gt;</span></span>
        const <span class="name ">beforeUnloadEvent</span>
        =
        <span class="constant-value">const _BeforeUnloadEventStreamProvider(&#39;beforeunload&#39;)</span>
    </section>

    <section class="desc markdown">
      <p>Static factory designed to expose <code>beforeunload</code> events to event
handlers that are not necessarily instances of <a href="dart-html/Window-class.html">Window</a>.</p>
<p>See <a href="dart-html/EventStreamProvider-class.html">EventStreamProvi