diff --git a/views/bootstrap/class.ViewDocument.php b/views/bootstrap/class.ViewDocument.php
index ea1063909..8a7513e41 100644
--- a/views/bootstrap/class.ViewDocument.php
+++ b/views/bootstrap/class.ViewDocument.php
@@ -551,7 +551,9 @@ $(document).ready( function() {
 				case 'application/pdf':
 					$this->contentHeading(getMLText("preview"));
 ?>
-			<iframe src="<?= $settings->_httpRoot ?>pdfviewer/web/viewer.html?file=<?php echo urlencode($settings->_httpRoot.'op/op.ViewOnline.php?documentid='.$latestContent->getDocument()->getID().'&version='.$latestContent->getVersion()); ?>" width="100%" height="700px"></iframe>
+			<div style="width:100%; height: 0; position:relative; padding-top: 141%;">
+			<iframe src="<?= $settings->_httpRoot ?>pdfviewer/web/viewer.html?file=<?php echo urlencode($settings->_httpRoot.'op/op.ViewOnline.php?documentid='.$latestContent->getDocument()->getID().'&version='.$latestContent->getVersion()); ?>" _width="100%" _height="100%" style="position: absolute; top: 0; left: 0; bottom: 0; right: 0; width:    100%; height: 100%"></iframe>
+			</div>
 <?php
 					break;
 				case 'image/svg+xml':
@@ -586,7 +588,9 @@ $(document).ready( function() {
 				if($pdfpreviewer->hasConverter($latestContent->getMimeType())) {
 					$this->contentHeading(getMLText("preview_pdf"));
 ?>
-				<iframe src="<?= $settings->_httpRoot ?>pdfviewer/web/viewer.html?file=<?php echo urlencode($settings->_httpRoot.'op/op.PdfPreview.php?documentid='.$latestContent->getDocument()->getID().'&version='.$latestContent->getVersion()); ?>" width="100%" height="700px"></iframe>
+				<div style="width:100%; height: 0; position:relative; padding-top: 141%;">
+				<iframe src="<?= $settings->_httpRoot ?>pdfviewer/web/viewer.html?file=<?php echo urlencode($settings->_httpRoot.'op/op.PdfPreview.php?documentid='.$latestContent->getDocument()->getID().'&version='.$latestContent->getVersion()); ?>" _width="100%" _height="700px" style="position: absolute; top: 0; left: 0; bottom: 0; right: 0; width:    100%; height: 100%"></iframe>
+				</div>
 <?php
 				}
 			}