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				@@ -468,12 +468,14 @@ var PDFLinkService = (function () { 
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				     get page() { 
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				       return this.pdfViewer.currentPageNumber; 
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				     }, 
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				+ 
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				     /** 
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				      * @param {number} value 
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				      */ 
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				     set page(value) { 
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				       this.pdfViewer.currentPageNumber = value; 
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				     }, 
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				+ 
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				     /** 
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				      * @param dest - The PDF destination object. 
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				      */ 
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				@@ -492,12 +494,14 @@ var PDFLinkService = (function () { 
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				           } 
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				           self.pdfViewer.scrollPageIntoView(pageNumber, dest); 
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				-          // Update the browsing history. 
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				-          self.pdfHistory.push({ 
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				-            dest: dest, 
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				-            hash: destString, 
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				-            page: pageNumber 
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				-          }); 
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				+          if (self.pdfHistory) { 
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				+            // Update the browsing history. 
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				+            self.pdfHistory.push({ 
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				+              dest: dest, 
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				+              hash: destString, 
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				+              page: pageNumber 
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				+            }); 
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				+          } 
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				         } else { 
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				           self.pdfDocument.getPageIndex(destRef).then(function (pageIndex) { 
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				             var pageNum = pageIndex + 1; 
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				@@ -576,7 +580,9 @@ var PDFLinkService = (function () { 
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				         var params = parseQueryString(hash); 
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				         // borrowing syntax from "Parameters for Opening PDF Files" 
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				         if ('nameddest' in params) { 
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				-          this.pdfHistory.updateNextHashParam(params.nameddest); 
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				+          if (this.pdfHistory) { 
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				+            this.pdfHistory.updateNextHashParam(params.nameddest); 
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				+          } 
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				           this.navigateTo(params.nameddest); 
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				           return; 
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				         } 
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				@@ -606,7 +612,7 @@ var PDFLinkService = (function () { 
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				                       zoomArgs.length > 1 ? (zoomArgs[1] | 0) : null]; 
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				             } else if (zoomArg === 'FitR') { 
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				               if (zoomArgs.length !== 5) { 
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				-                console.error('pdfViewSetHash: ' + 
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				+                console.error('PDFLinkService_setHash: ' + 
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				                               'Not enough parameters for \'FitR\'.'); 
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				               } else { 
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				                 dest = [null, { name: zoomArg }, 
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				@@ -614,7 +620,7 @@ var PDFLinkService = (function () { 
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				                         (zoomArgs[3] | 0), (zoomArgs[4] | 0)]; 
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				               } 
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				             } else { 
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				-              console.error('pdfViewSetHash: \'' + zoomArg + 
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				+              console.error('PDFLinkService_setHash: \'' + zoomArg + 
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				                             '\' is not a valid zoom value.'); 
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				             } 
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				           } 
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				@@ -636,7 +642,9 @@ var PDFLinkService = (function () { 
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				       } else if (/^\d+$/.test(hash)) { // page number 
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				         this.page = hash; 
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				       } else { // named destination 
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				-        this.pdfHistory.updateNextHashParam(unescape(hash)); 
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				+        if (this.pdfHistory) { 
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				+          this.pdfHistory.updateNextHashParam(unescape(hash)); 
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				+        } 
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				         this.navigateTo(unescape(hash)); 
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				       } 
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				     }, 
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				@@ -648,11 +656,15 @@ var PDFLinkService = (function () { 
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				       // See PDF reference, table 8.45 - Named action 
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				       switch (action) { 
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				         case 'GoBack': 
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				-          this.pdfHistory.back(); 
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				+          if (this.pdfHistory) { 
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				+            this.pdfHistory.back(); 
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				+          } 
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				           break; 
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				         case 'GoForward': 
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				-          this.pdfHistory.forward(); 
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				+          if (this.pdfHistory) { 
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				+            this.pdfHistory.forward(); 
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				+          } 
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				           break; 
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				         case 'NextPage': 
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