diff --git a/Firefox/content_scripts/updatePage.js b/Firefox/content_scripts/updatePage.js
new file mode 100644
index 0000000..6ac0afb
--- /dev/null
+++ b/Firefox/content_scripts/updatePage.js
@@ -0,0 +1,76 @@
+function isClassSmartReader(elementsToAnalyse, ourClass) {
+
+    /* Check a parent class going down
+
+    Args:
+        elementsToAnalyse: elements to analyse
+        ourClass: class to search
+
+    Returns:
+        bool: if we found the class or not
+
+    */
+
+    for(var i = 0 ; i < elementsToAnalyse.children.length ; i++) {
+
+        if(elementsToAnalyse.children[i].className === ourClass) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+function watchPageUpdates() {
+
+    var observePageUpdates = new MutationObserver(updatePage);
+    var container = document.body;
+    var config = {childList: true, subtree:true };
+
+    browser.runtime.sendMessage({mode: "state"}, function(message) {
+
+        if(message.mode === "enable") {
+    
+            observePageUpdates.observe(container, config);
+
+        } else {
+
+            observePageUpdates.disconnect();
+        }
+    });
+    
+}
+
+function updatePage(mutationList, observer) {
+    /* Update the page when a new DOM appears
+
+    */
+
+    observer.disconnect();
+    
+    var allElements = [];
+    var tempElements = [];
+    var finalElements = [];
+
+    //Grouping
+    assembleElements(document.body.getElementsByTagName("P"), allElements);
+    assembleElements(document.body.getElementsByTagName("SPAN"), allElements);
+    assembleElements(document.body.getElementsByTagName("DIV"), allElements);
+    assembleElements(document.body.getElementsByTagName("BR"), allElements);
+    assembleElements(document.body.getElementsByTagName("BLOCKQUOTE"), allElements);
+    assembleElements(document.body.getElementsByTagName("EM"), allElements);
+
+    filterElements(allElements, tempElements);
+
+    for(var i = 0 ; i < tempElements.length ; i++) {
+
+        if(isClassSmartReader(tempElements[i], "smartReader-remove") === false && tempElements[i].className !== "smartReader-remove" && tempElements[i].parentNode.className !== "smartReader-remove") {
+
+            finalElements.push(tempElements[i]);
+        }
+    }
+
+    modifyHtml(finalElements);
+
+    watchPageUpdates();
+}
\ No newline at end of file
diff --git a/Firefox/main.js b/Firefox/main.js
index 13105ac..aa54858 100644
--- a/Firefox/main.js
+++ b/Firefox/main.js
@@ -25,6 +25,7 @@ function main() {
 
     modifyHtml(finalElements);
 
+    watchPageUpdates();
 }
 
 //Is addon actived => launch the main function on the page
diff --git a/Firefox/manifest.json b/Firefox/manifest.json
index bdfacca..4a9e305 100644
--- a/Firefox/manifest.json
+++ b/Firefox/manifest.json
@@ -35,6 +35,7 @@
         "/content_scripts/textAtRoot.js",
         "/content_scripts/isAddonActived.js",
         "/content_scripts/isItLetter.js",
+        "/content_scripts/updatePage.js",
         "main.js"
       ]
     }