window.onload = function(){
//DsPdfViewer.LicenseKey = "***key***";
let viewer = new DsPdfViewer("#viewer", { language: "ja" });
viewer.addDefaultPanels();
// PDFを開いた後、10ページ目に移動します。
viewer.onAfterOpen.register(function () {
viewer.pageIndex = 9;
});
viewer.open("/diodocs/pdfviewer/demos/product-bundles/assets/pdf/diodocs_a4_full.pdf");
}
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>コードによるページ移動</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="./src/styles.css">
<script src="/diodocs/pdfviewer/demos/product-bundles/build/dspdfviewer.js"></script>
<script src="/diodocs/pdfviewer/demos/product-bundles/build/wasmSupportApi.js"></script>
<script src="/diodocs/pdfviewer/demos/resource/js/init.js"></script>
<script src="./src/app.js"></script>
</head>
<body>
<div id="viewer"></div>
</body>
</html>
#viewer {
height: 100%;
}