Merge pull request #404 from notmasteryet/tree-9

Fixing back-button/NaN-hash issue

web/viewer.js

@@ -42,7 +42,7 @@ var PDFView = {
   set page(val) {
     var pages = this.pages;
     var input = document.getElementById('pageNumber');
-    if (val <= 0 || val > pages.length) {
+    if (!(0 < val && val <= pages.length)) {
       input.value = this.page;
       return;
     }
@@ -58,7 +58,7 @@ var PDFView = {
   },
 
   get page() {
-    return parseInt(document.location.hash.substring(1));
+    return parseInt(document.location.hash.substring(1)) || 1;
   },
 
   open: function(url, scale) {