Merge pull request #6617 from Snuffleupagus/issue-6615

Correctly handle /FitH destinations with `null` as the parameter

web/pdf_viewer.js

@@ -519,6 +519,12 @@ var PDFViewer = (function pdfViewer() {
         case 'FitBH':
           y = dest[2];
           scale = 'page-width';
+          // According to the PDF spec, section 12.3.2.2, a `null` value in the
+          // parameter should maintain the position relative to the new page.
+          if (y === null && this._location) {
+            x = this._location.left;
+            y = this._location.top;
+          }
           break;
         case 'FitV':
         case 'FitBV':