Fixing: The problem with WKUserScript initialization on iOS 14 and later.

Example/Podfile

@@ -1,4 +1,4 @@
-platform :ios, '9.0'
+platform :ios, '10.0'
 
 use_frameworks!
 inhibit_all_warnings!

Example/Podfile.lock

@@ -25,7 +25,7 @@ DEPENDENCIES:
   - Quick (= 1.3.2)
 
 SPEC REPOS:
-  https://github.com/cocoapods/specs.git:
+  https://github.com/CocoaPods/Specs.git:
     - AEXML
     - FontBlaster
     - MenuItemKit
@@ -42,7 +42,7 @@ EXTERNAL SOURCES:
 
 SPEC CHECKSUMS:
   AEXML: 601f41fcaa7bda7605cad153b0f43db9ec006c0f
-  FolioReaderKit: 6b5daca560b3dd6905ab14870f4823d7e1f283de
+  FolioReaderKit: e9842c8058ffa170f0574e45b2761498cfef90c4
   FontBlaster: 127aa66419478d1c62926c7fdb39841633344a45
   MenuItemKit: 0f850e630b0a3d2bd80fec54db87ce0d2077ada2
   Nimble: 04f732da099ea4d153122aec8c2a88fd0c7219ae
@@ -52,6 +52,6 @@ SPEC CHECKSUMS:
   SSZipArchive: 14401ade5f8e82aba1ff03e9f88e9de60937ae60
   ZFDragableModalTransition: 0d294eaaba6edfcb9839595de765f9ca06a4b524
 
-PODFILE CHECKSUM: f5840071ca5121876c1758f6405302b47804dd07
+PODFILE CHECKSUM: 9b0cc9f299a29c5423503d26bd566e7f7bffcb6d
 
-COCOAPODS: 1.7.5
+COCOAPODS: 1.11.2

FolioReaderKit.podspec

@@ -14,7 +14,7 @@ Pod::Spec.new do |s|
   s.social_media_url = 'https://twitter.com/hebertialmeida'
 
   s.swift_version = '4.2'
-  s.platform      = :ios, '9.0'
+  s.platform      = :ios, '10.0'
   s.requires_arc  = true
 
   s.source_files = [

Source/FolioReaderAudioPlayer.swift

@@ -382,22 +382,19 @@ open class FolioReaderAudioPlayer: NSObject {
         }
 
         let playbackActiveClass = book.playbackActiveClass
-        guard let sentence = currentPage.webView?.js("getSentenceWithIndex('\(playbackActiveClass)')") else {
-            if (readerCenter.isLastPage() == true) {
-                self.stop()
-            } else {
-                readerCenter.changePageToNext()
+        currentPage.webView?.js("getSentenceWithIndex('\(playbackActiveClass)')") { sentence in
+            guard let sentence = sentence else {
+                if (readerCenter.isLastPage() == true) {
+                    self.stop()
+                } else {
+                    readerCenter.changePageToNext()
+                }
+                return
             }
-
-            return
+            guard let href = readerCenter.getCurrentChapter()?.href else { return }
+            // TODO QUESTION: The previous code made it possible to call `playText` with the parameter `href` being an empty string. Was that valid? should this logic be kept?
+            self.playText(href, text: sentence)
         }
-
-        guard let href = readerCenter.getCurrentChapter()?.href else {
-            return
-        }
-
-        // TODO QUESTION: The previous code made it possible to call `playText` with the parameter `href` being an empty string. Was that valid? should this logic be kept?
-        self.playText(href, text: sentence)
     }
 
     func readCurrentSentence() {

Source/FolioReaderCenter.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 import ZFDragableModalTransition
+import WebKit
 
 /// Protocol which is used from `FolioReaderCenter`s.
 @objc public protocol FolioReaderCenterDelegate: class {
@@ -464,17 +465,11 @@ open class FolioReaderCenter: UIViewController, UICollectionViewDelegate, UIColl
         guard var html = try? String(contentsOfFile: resource.fullHref, encoding: String.Encoding.utf8) else {
             return cell
         }
+
+        // Inject viewport
+        let viewportTag = "<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0, shrink-to-fit=no\">"
 
-        let mediaOverlayStyleColors = "\"\(self.readerConfig.mediaOverlayColor.hexString(false))\", \"\(self.readerConfig.mediaOverlayColor.highlightColor().hexString(false))\""
-
-        // Inject CSS
-        let jsFilePath = Bundle.frameworkBundle().path(forResource: "Bridge", ofType: "js")
-        let cssFilePath = Bundle.frameworkBundle().path(forResource: "Style", ofType: "css")
-        let cssTag = "<link rel=\"stylesheet\" type=\"text/css\" href=\"\(cssFilePath!)\">"
-        let jsTag = "<script type=\"text/javascript\" src=\"\(jsFilePath!)\"></script>" +
-        "<script type=\"text/javascript\">setMediaOverlayStyleColors(\(mediaOverlayStyleColors))</script>"
-
-        let toInject = "\n\(cssTag)\n\(jsTag)\n</head>"
+        let toInject = "\n\(viewportTag)\n</head>"
         html = html.replacingOccurrences(of: "</head>", with: toInject)
 
         // Font class name
@@ -648,18 +643,13 @@ open class FolioReaderCenter: UIViewController, UICollectionViewDelegate, UIColl
         }
 
         scrollScrubber?.setSliderVal()
-
-        if let readingTime = currentPage.webView?.js("getReadingTime()") {
-            pageIndicatorView?.totalMinutes = Int(readingTime)!
-        } else {
-            pageIndicatorView?.totalMinutes = 0
+        currentPage.webView?.js("getReadingTime()") { readingTime in
+            self.pageIndicatorView?.totalMinutes = Int(readingTime ?? "0")!
+            self.pagesForCurrentPage(currentPage)
+            self.delegate?.pageDidAppear?(currentPage)
+            self.delegate?.pageItemChanged?(self.getCurrentPageItemNumber())
+            completion?()
         }
-        pagesForCurrentPage(currentPage)
-
-        delegate?.pageDidAppear?(currentPage)
-        delegate?.pageItemChanged?(self.getCurrentPageItemNumber())
-
-        completion?()
     }
 
     func pagesForCurrentPage(_ page: FolioReaderPage?) {
@@ -1075,9 +1065,10 @@ open class FolioReaderCenter: UIViewController, UICollectionViewDelegate, UIColl
     @objc func shareChapter(_ sender: UIBarButtonItem) {
         guard let currentPage = currentPage else { return }
 
-        if let chapterText = currentPage.webView?.js("getBodyText()") {
+        currentPage.webView?.js("getBodyText()") { chapterText in
+            guard let chapterText = chapterText else { return }
             let htmlText = chapterText.replacingOccurrences(of: "[\\n\\r]+", with: "<br />", options: .regularExpression)
-            var subject = readerConfig.localizedShareChapterSubject
+            var subject = self.readerConfig.localizedShareChapterSubject
             var html = ""
             var text = ""
             var bookTitle = ""
@@ -1092,7 +1083,7 @@ open class FolioReaderCenter: UIViewController, UICollectionViewDelegate, UIColl
             }
 
             // Get chapter name
-            if let chapter = getCurrentChapterName() {
+            if let chapter = self.getCurrentChapterName() {
                 chapterName = chapter
             }
 
@@ -1104,17 +1095,17 @@ open class FolioReaderCenter: UIViewController, UICollectionViewDelegate, UIColl
             // Sharing html and text
             html = "<html><body>"
             html += "<br /><hr> <p>\(htmlText)</p> <hr><br />"
-            html += "<center><p style=\"color:gray\">"+readerConfig.localizedShareAllExcerptsFrom+"</p>"
+            html += "<center><p style=\"color:gray\">"+self.readerConfig.localizedShareAllExcerptsFrom+"</p>"
             html += "<b>\(bookTitle)</b><br />"
-            html += readerConfig.localizedShareBy+" <i>\(authorName)</i><br />"
-
-            if let bookShareLink = readerConfig.localizedShareWebLink {
+            html += self.readerConfig.localizedShareBy+" <i>\(authorName)</i><br />"
+            
+            if let bookShareLink = self.readerConfig.localizedShareWebLink {
                 html += "<a href=\"\(bookShareLink.absoluteString)\">\(bookShareLink.absoluteString)</a>"
                 shareItems.append(bookShareLink as AnyObject)
             }
 
             html += "</center></body></html>"
-            text = "\(chapterName)\n\n“\(chapterText)” \n\n\(bookTitle) \n\(readerConfig.localizedShareBy) \(authorName)"
+            text = "\(chapterName)\n\n“\(chapterText)” \n\n\(bookTitle) \n\(self.readerConfig.localizedShareBy) \(authorName)"
 
             let act = FolioReaderSharingProvider(subject: subject, text: text, html: html)
             shareItems.insert(contentsOf: [act, "" as AnyObject], at: 0)
@@ -1127,7 +1118,7 @@ open class FolioReaderCenter: UIViewController, UICollectionViewDelegate, UIColl
                 actv.barButtonItem = sender
             }
 
-            present(activityViewController, animated: true, completion: nil)
+           self.present(activityViewController, animated: true, completion: nil)
         }
     }
 
@@ -1281,7 +1272,7 @@ open class FolioReaderCenter: UIViewController, UICollectionViewDelegate, UIColl
         // Perform the page after a short delay as the collection view hasn't completed it's transition if this method is called (the index paths aren't right during fast scrolls).
         delay(0.2, closure: { [weak self] in
             if (self?.readerConfig.scrollDirection == .horizontalWithVerticalContent),
-                let cell = ((scrollView.superview as? UIWebView)?.delegate as? FolioReaderPage) {
+                let cell = ((scrollView.superview as? WKWebView)?.navigationDelegate as? FolioReaderPage) {
                 let currentIndexPathRow = cell.pageNumber - 1
                 self?.currentWebViewScrollPositions[currentIndexPathRow] = scrollView.contentOffset
             }