尝试以下代码：

<p>Click the button below to start the download:</p>
<button id="downloadButton" onclick="startDownload()">Download</button>

<script>
  function startDownload() {
    document.getElementById("downloadButton").innerHTML = "Please wait...";
    setTimeout(function () {
      window.location.href = "YOUR_DOWNLOAD_LINK_HERE";
    }, 30000); // 30 seconds delay
  }
</script>

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