Added startup bootloop crash protection

Former-commit-id: 99314185e95591d593378b49b1270041f8cabbdb [formerly bdf19cb0b51ff31fedc57ded86c9071067d5bd39]
Former-commit-id: 53da94c64ca856c1ecf81e154f04b30382c656b0

www/js/app.js

@@ -1724,6 +1724,10 @@ define(['jquery', 'zimArchiveLoader', 'util', 'uiUtil', 'cookies', 'q', 'module'
                 console.log("Initiating Document Ready timer...");
                 console.time("Time to Document Ready");
 
+                //Set startup cookie to guard against boot loop
+                //Cookie will signal failure until article is fully loaded
+                document.cookie = 'lastPageLoad=failed;expires=Fri, 31 Dec 9999 23:59:59 GMT';
+
                 //Void the localSearch variable to prevent invalid DOM references remainining [kiwix-js-windows #56]
                 localSearch = {};
 
@@ -2313,6 +2317,9 @@ define(['jquery', 'zimArchiveLoader', 'util', 'uiUtil', 'cookies', 'q', 'module'
 
                     loadImages();
                     //loadJavascript(); //Disabled for now, since it does nothing - also, would have to load before images, ideally through controlled css loads above
+
+                    //Document has loaded except for images, so we can now change the startup cookie (and delete) [see init.js]
+                    document.cookie = 'lastPageLoad=success;expires=Thu, 21 Sep 1979 00:00:01 UTC';
                 }
 
             } //End of injectHTML()

www/js/init.js

@@ -60,6 +60,14 @@ params['allowInternetAccess'] = params['allowInternetAccess'] || false; //Do not
 params['printIntercept'] = false;
 params['printInterception'] = false;
 
+//Prevent app boot loop with problematic pages that cause an app crash
+if (getCookie('lastPageLoad') == 'failed') {
+    params.lastPageVisit = "";
+} else {
+    //Cookie will signal failure until article is fully loaded
+    document.cookie = 'lastPageLoad=failed;expires=Fri, 31 Dec 9999 23:59:59 GMT';
+}
+
 //Initialize checkbox, radio and other values
 document.getElementById('cssCacheModeCheck').checked = params.cssCache;
 document.getElementById('imageDisplayModeCheck').checked = params.imageDisplay;