diff --git a/cps/static/js/reading/epub-progress.js b/cps/static/js/reading/epub-progress.js
index 4141b485..58fb60ea 100644
--- a/cps/static/js/reading/epub-progress.js
+++ b/cps/static/js/reading/epub-progress.js
@@ -20,6 +20,7 @@ class EpubParser {
     }
 
     /**
+     * gets file from files and returns decompressed content as string
      * @param {string} filename name of the file in filelist
      * @return {string} string representation of decompressed bytes
      */
@@ -44,7 +45,7 @@ class EpubParser {
      resolves an idref in content.opf to its file
      */
     resolveIDref(idref) {
-        return this.opfXml.getElementById(idref).getAttribute("href");
+        return this.absPath(this.opfXml.getElementById(idref).getAttribute("href"));
     }
 
     /**
@@ -67,7 +68,7 @@ class EpubParser {
         let bytesize = 0;
         for (let file of this.getSpine()) {
             if (file !== currentFile) {
-                let filepath = this.absPath(this.resolveIDref(file));
+                let filepath = this.resolveIDref(file);
                 //ignore non text files
                 if (filepath.endsWith("html")) {
                     console.log(filepath + " " + bytesize)
@@ -79,34 +80,89 @@ class EpubParser {
         }
         return bytesize;
     }
-    cfiToXmlNode(file,cfi){
+
+    /**
+     * resolves the given cfi to the xml node it points to
+     * @param {string} cfi epub-cfi string in the form: epubcfi(/6/16[id13]!/4[id2]/4/2[doc12]/1:0)
+     * @return XML Text-Node
+     */
+    cfiToXmlNode(cfi) {
+        let cfiPath = cfi.split("(")[1].split(")")[0];
+        let fileId = cfiPath.split("!")[0].split("[")[1].split("]")[0];
+        let xml = this.parser.parseFromString(this.decompress(this.resolveIDref(fileId)), "text/xml");
+        let components = cfiPath.split("!")[1].split("/").slice(1);
+        let currentNode = xml.getElementsByTagName("html")[0];
+        for (const component of components) {
+            this.validateChildNodes(currentNode);
+            console.log(currentNode);
+            console.log(component);
+            let index = 0;
+            if (component.includes("[")) {
+                index = parseInt(component.split("[")[0]) - 1;
+                currentNode = currentNode.childNodes[index];
+                console.assert(currentNode.getAttribute("id") === component.split("[")[1].split("]")[0], "failed to resolve node");
+            } else if (component.includes(":")) {
+                index = component.split(":")[0] - 1;
+                return currentNode.childNodes[index]; //exit point
+            } else {
+                index = parseInt(component);
+                currentNode = currentNode.childNodes[index - 1];
+            }
+        }
+    }
+
+    /**
+     * inserts missing text/element nodes to keep them alternating
+     * @param {*} parentNode
+     */
+    validateChildNodes(parentNode) {
+        for (let index = 0; index < parentNode.childNodes.length;) {
+            const element = parentNode.childNodes[index];
+            if (index % 2 === 0 && element.nodeType === 1) {
+                element.parentNode.insertBefore(parentNode.ownerDocument.createTextNode(""), element);
+                continue;
+            }
+            if (index % 2 === 1 && element.nodeType === 3) {
+                element.insertBefore(parentNode.ownerDocument.createElement("")); //TODO check
+                continue;
+            }
+            index++;
+        }
 
     }
+
     /**
-    takes the node that the cfi points at and counts the bytes of all nodes before that
+     takes the node that the cfi points at and counts the bytes of all nodes before that
      */
-    getCurrentFileProgress(currentFile, CFI) {
-        let size = 0
-        let startnode = this.cfiToXmlNode(currentFile,CFI);
-        let prev = startnode.previousElementSibling;
+    getCurrentFileProgress(CFI) {
+        let size = parseInt(CFI.split(":")[1])//text offset in node
+        let startnode = this.cfiToXmlNode(CFI); //returns text node
+        let xmlnsLength = startnode.parentNode.namespaceURI.length;
+        let prev = startnode.parentNode.previousElementSibling;
         while (prev !== null) {
-            size += this.encoder.encode(prev.outerHTML).length;
+            console.log("size: "+size)
+            console.log(prev.outerHTML)
+            console.log(this.encoder.encode(prev.outerHTML).length - xmlnsLength)
+            size += this.encoder.encode(prev.outerHTML).length - xmlnsLength;
             prev = prev.previousElementSibling;
         }
-        let parent = startnode.parentElement;
+        let parent = startnode.parentElement.parentElement;
         while (parent !== null) {
             let parentPrev = parent.previousElementSibling;
             while (parentPrev !== null) {
-                size += this.encoder.encode(parentPrev.outerHTML).length;
+                console.log(parentPrev.outerHTML)
+                console.log(this.encoder.encode(parentPrev.outerHTML).length - xmlnsLength)
+
+                size += this.encoder.encode(parentPrev.outerHTML).length - xmlnsLength;
                 parentPrev = parentPrev.previousElementSibling;
             }
-            parent=parent.parentElement;
+            parent = parent.parentElement;
         }
         return size;
     }
 
     getProgress(currentFile, CFI) {
-        let percentage = this.getTotalByteLength() / (this.getPreviousFilesSize(currentFile) + this.getCurrentFileProgress(currentFile, CFI));
+        let percentage = this.getTotalByteLength() / (this.getPreviousFilesSize(currentFile) + this.getCurrentFileProgress(CFI));
         if (percentage === Infinity) {
             return 0;
         } else {
@@ -114,3 +170,5 @@ class EpubParser {
         }
     }
 }
+
+e = new EpubParser(reader.book.archive.zip.files)