diff --git a/js/FSMDocument.js b/js/FSMDocument.js
new file mode 100644
index 0000000..17826df
--- /dev/null
+++ b/js/FSMDocument.js
@@ -0,0 +1,80 @@
+class FSMDocument {
+
+    constructor(name) {
+        this.id = guid();
+        this.name = null;
+        this.createdAt = Date.now();
+        this.lastModified = Date.now();
+        this.element = null;
+        this.unsaved = true;
+        this.lastSavedHash = '';
+        this.states = [];
+        this.connections = [];
+    }
+
+    tick() {
+        this.states.forEach(stateA => {
+            this.states.forEach(stateB => {
+                if (stateA !== stateB && stateA.intersects(stateB)) {
+                    const inter = stateA.intersection(stateB);
+                    const angle1 = stateA.directionTo(stateB);
+                    const angle2 = angle1 + Math.PI;
+
+                    const x1 = Math.cos(angle1) * inter + stateA.x;
+                    const y1 = Math.sin(angle1) * inter + stateA.y;
+                    const x2 = Math.cos(angle2) * inter + stateB.x;
+                    const y2 = Math.sin(angle2) * inter + stateB.y;
+
+                    stateA.moveTo(x1, y1);
+                    stateB.moveTo(x2, y2);
+                }
+            });
+        });
+
+        this.states.forEach(state => {
+            if (state.v) {
+                state.moveToStep();
+            }
+        });
+
+        if(!this.unsaved) {
+            if(this.hashCode() !== this.lastSavedHash) {
+                this.unsaved = true;
+                this.element.classList.add('unsaved');
+            }
+        }
+    }
+
+    draw() {
+        this.states.forEach(state => state.draw());
+        this.connections.forEach(connection => connection.draw());
+    }
+
+    onDblClick(x, y) {
+        if (!selectedObject) {
+            selectedObject = new State(x, y);
+            this.states.push(selectedObject);
+            resetCaret();
+        } else if (selectedObject instanceof State) {
+            selectedObject.isAcceptState = !selectedObject.isAcceptState;
+        }
+    }
+
+    deleteCurrentObject() {
+        if (!!selectedObject) {
+            if (selectedObject instanceof State) {
+                this.states.splice(this.states.findIndex(state => state === selectedObject), 1);
+            }
+
+            for (let i = 0; i < this.connections.length; i++) {
+                const con = this.connections[i];
+                if (con === selectedObject || con.state === selectedObject || con.stateA === selectedObject || con.stateB === selectedObject) {
+                    this.connections.splice(i--, 1);
+                }
+            }
+
+            selectedObject = null;
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/js/main.js b/js/main.js
index ddd7300..2df2ade 100644
--- a/js/main.js
+++ b/js/main.js
@@ -14,14 +14,79 @@ const settings = {
     }
 };
 
+const elements = {
+    documents: document.getElementById('document-tabs'),
+};
+
 const canvas = document.getElementById('canvas');
 const ctx = canvas.getContext('2d');
 
 canvas.width = width;
 canvas.height = height;
 
-const states = [];
-const connections = [];
+const documents = [];
+let activeDocument = null;
+
+function switchDocument(doc) {
+    if (doc instanceof FSMDocument) {
+        doc = documents.findIndex(document => document === doc);
+    }
+
+    if (typeof doc === 'number' && doc >= 0 && doc < documents.length) {
+        activeDocument = doc;
+
+        const docElements = document.getElementsByClassName('document-tab');
+        for (let el of docElements) {
+            el.classList.remove('active');
+        }
+        docElements[doc].classList.add('active');
+
+        resetCaret();
+        selectedObject = null;
+        currentConnection = null;
+        movingObject = false;
+        originalClick = null;
+        deltaMouseX = 0;
+        deltaMouseY = 0;
+        shiftPressed = false;
+    }
+}
+
+function addDocument(doc) {
+    documents.push(doc);
+
+    const elem = document.createElement('li');
+    elem.classList.add('document-tab');
+
+    elem.addChild('span', 'document-name', doc.name || 'Unbenannt');
+    const btn = elem.addChild('button', ['btn', 'btn-close'], 'X');
+
+    elem.addEventListener('click', () => {
+        switchDocument(doc);
+    });
+
+    btn.addEventListener('click', () => {
+        closeDocument(doc);
+    });
+
+    doc.element = elem;
+
+    elements.documents.appendChild(elem);
+}
+
+function closeDocument(doc) {
+    if (doc instanceof Document) {
+        doc = documents.findIndex(document => document === doc);
+    }
+
+    if (typeof doc === 'number') {
+        documents.splice(doc, 1);
+
+        const docElements = document.getElementsByClassName('document-tab');
+        docElements[doc].remove();
+    }
+}
+
 const animations = [];
 
 let isPaused = false;
@@ -46,29 +111,9 @@ function resetCaret() {
 }
 
 function tick() {
-    states.forEach(stateA => {
-        states.forEach(stateB => {
-            if (stateA !== stateB && stateA.intersects(stateB)) {
-                const inter = stateA.intersection(stateB);
-                const angle1 = stateA.directionTo(stateB);
-                const angle2 = angle1 + Math.PI;
-
-                const x1 = Math.cos(angle1) * inter + stateA.x;
-                const y1 = Math.sin(angle1) * inter + stateA.y;
-                const x2 = Math.cos(angle2) * inter + stateB.x;
-                const y2 = Math.sin(angle2) * inter + stateB.y;
-
-                stateA.moveTo(x1, y1);
-                stateB.moveTo(x2, y2);
-            }
-        });
-    });
-
-    states.forEach(state => {
-        if (state.v) {
-            state.moveToStep();
-        }
-    });
+    if (activeDocument !== null) {
+        documents[activeDocument].tick();
+    }
 
     if (!isPaused)
         setTimeout(tick, 1000 / 30);
@@ -79,9 +124,9 @@ function draw() {
     ctx.save();
     ctx.translate(0.5, 0.5);
 
-    states.forEach(state => state.draw());
-
-    connections.forEach(connection => connection.draw());
+    if (activeDocument !== null) {
+        documents[activeDocument].draw();
+    }
 
     if (!!currentConnection) {
         currentConnection.draw();
@@ -96,13 +141,19 @@ function draw() {
 }
 
 function selectObject(x, y) {
-    for (let state of states) {
+    if (activeDocument === null) {
+        return null;
+    }
+
+    const doc = documents[activeDocument];
+
+    for (let state of doc.states) {
         if (state.containsPoint(x, y)) {
             return state;
         }
     }
 
-    for (let connection of connections) {
+    for (let connection of doc.connections) {
         if (connection.containsPoint(x, y)) {
             return connection;
         }
@@ -184,13 +235,13 @@ canvas.addEventListener('mousemove', (event) => {
 
 });
 
-canvas.addEventListener('mouseup', (event) => {
+canvas.addEventListener('mouseup', () => {
     movingObject = false;
 
-    if (!!currentConnection) {
+    if (!!currentConnection && activeDocument !== null) {
         if (!(currentConnection instanceof TemporaryConnection)) {
             selectedObject = currentConnection;
-            connections.push(currentConnection);
+            documents[activeDocument].connections.push(currentConnection);
             resetCaret();
         }
         currentConnection = null;
@@ -199,15 +250,13 @@ canvas.addEventListener('mouseup', (event) => {
 
 canvas.addEventListener('dblclick', (event) => {
     const mouse = cbRelMousePos(event);
+
+    if (activeDocument === null)
+        return;
+
     selectedObject = selectObject(mouse.x, mouse.y);
 
-    if (!selectedObject) {
-        selectedObject = new State(mouse.x, mouse.y);
-        states.push(selectedObject);
-        resetCaret();
-    } else if (selectedObject instanceof State) {
-        selectedObject.isAcceptState = !selectedObject.isAcceptState;
-    }
+    documents[activeDocument].onDblClick(mouse.x, mouse.y);
 });
 
 document.addEventListener('keydown', (event) => {
@@ -217,8 +266,6 @@ document.addEventListener('keydown', (event) => {
         return true;
     }
 
-    console.log(key);
-
     switch (key) {
         case 16: // Shift
             shiftPressed = true;
@@ -233,31 +280,27 @@ document.addEventListener('keydown', (event) => {
 
             return false;
         case 37: // Left Arrow
-            caretPos--;
-            caretPos = Math.max(caretPos, 0);
-            resetCaret();
+            if (!(event.ctrlKey || event.metaKey) && !!selectedObject) {
+                caretPos--;
+                caretPos = Math.max(caretPos, 0);
+                resetCaret();
 
-            return false;
+                return false;
+            }
+
+            break;
         case 39: // Right Arrow
-            caretPos++;
-            caretPos = Math.min(caretPos, selectedObject.text.length);
-            resetCaret();
+            if (!(event.ctrlKey || event.metaKey) && !!selectedObject) {
+                caretPos++;
+                caretPos = Math.min(caretPos, selectedObject.text.length);
+                resetCaret();
 
-            return false;
+                return false;
+            }
+            break;
         case 46: // Delete
-            if (!!selectedObject) {
-                if (selectedObject instanceof State) {
-                    states.splice(states.findIndex(state => state === selectedObject), 1);
-                }
-
-                for (let i = 0; i < connections.length; i++) {
-                    const con = connections[i];
-                    if (con === selectedObject || con.state === selectedObject || con.stateA === selectedObject || con.stateB === selectedObject) {
-                        connections.splice(i--, 1);
-                    }
-                }
-
-                selectedObject = null;
+            if (activeDocument !== null) {
+                documents[activeDocument].deleteCurrentObject();
             }
             break;
     }
@@ -281,8 +324,6 @@ document.addEventListener('keypress', (event) => {
     if (!!selectedObject && 'text' in selectedObject) {
         const text = selectedObject.text;
 
-        console.log(key, event);
-
         if (!event.metaKey && !event.altKey && !event.ctrlKey) {
             if (key >= 0x20 && key <= 0x7E) {
                 selectedObject.text = text.substring(0, caretPos) + String.fromCharCode(key) + text.substring(caretPos, text.length);
@@ -291,8 +332,6 @@ document.addEventListener('keypress', (event) => {
 
                 return false;
             }
-
-            console.log(caretPos);
         }
     }
 
@@ -302,8 +341,43 @@ document.addEventListener('keypress', (event) => {
 });
 
 window.addEventListener('keydown', (event) => {
-    if ((event.ctrlKey || event.metaKey) && String.fromCharCode(event.which).toLowerCase() === 's') {
-        exportToFile();
+    const keyCode = crossBrowserKey(event);
+    const key = String.fromCharCode(keyCode).toLowerCase();
+    if ((event.ctrlKey || event.metaKey) && key === 's') { // Ctrl + S
+        if (event.altKey || event.shiftKey) { // Ctrl + Alt + S
+            modalExport.open();
+        } else {
+            saveToLocalStorage();
+        }
+
+        event.preventDefault();
+        return false;
+    }
+
+    if ((event.ctrlKey || event.metaKey) && key === 'e') { // Ctrl + E
+        modalExport.open();
+
+        event.preventDefault();
+        return false;
+    }
+
+    if ((event.ctrlKey || event.metaKey) && keyCode === 37) { // Ctrl + LeftArrow
+        let activeDoc = activeDocument;
+        activeDoc--;
+        activeDoc = activeDoc < 0 ? documents.length - 1 : activeDoc % documents.length;
+
+        switchDocument(activeDoc);
+
+        event.preventDefault();
+        return false;
+    }
+
+    if ((event.ctrlKey || event.metaKey) && keyCode === 39) { // Ctrl + RightArrow
+        let activeDoc = activeDocument;
+        activeDoc++;
+        activeDoc = activeDoc < 0 ? documents.length - 1 : activeDoc % documents.length;
+
+        switchDocument(activeDoc);
 
         event.preventDefault();
         return false;
@@ -361,8 +435,26 @@ CanvasRenderingContext2D.prototype.drawText = function (originalText, x, y, angl
     }
 };
 
+Node.prototype.addChild = function (name, classList, text) {
+    const elem = document.createElement(name);
+
+    if (classList instanceof Array) {
+        elem.classList.add(...classList);
+    } else if (!!classList) {
+        elem.classList.add(classList);
+    }
+
+    if (!!text) {
+        elem.innerText = text;
+    }
+
+    this.appendChild(elem);
+
+    return elem;
+};
+
 function snapNode(targetState) {
-    for (let state of states) {
+    for (let state of documents[activeDocument].states) {
         if (state === targetState)
             continue;
 
@@ -415,15 +507,43 @@ function cbRelMousePos(event) {
     };
 }
 
-tick();
-draw();
-
 function guid() {
     function s4() {
         return Math.floor((1 + Math.random()) * 0x10000)
             .toString(16)
             .substring(1);
     }
+
     return s4() + s4() + '-' + s4() + '-' + s4() + '-' +
         s4() + '-' + s4() + s4() + s4();
-}
\ No newline at end of file
+}
+
+window.addEventListener('load', () => {
+    const doc = new FSMDocument('Dokument1');
+    addDocument(doc);
+    switchDocument(doc);
+
+    tick();
+    draw();
+});
+
+Object.prototype.hashCode = function () {
+    let baseString = '';
+    Object.values(this).forEach(entry => {
+        if (entry === null)
+            return;
+
+        if (typeof entry === 'object' && !(entry instanceof Node)) {
+            baseString += entry.hashCode();
+        } else {
+            baseString += entry;
+        }
+    });
+    let hash = 0;
+    for (let i = 0; i < baseString.length; i++) {
+        const char = baseString.charCodeAt(i);
+        hash = ((hash << 5) - hash) + char;
+        hash = hash & hash;
+    }
+    return hash;
+};
\ No newline at end of file
diff --git a/js/simulate.js b/js/simulate.js
index 2b46f1b..28b003f 100644
--- a/js/simulate.js
+++ b/js/simulate.js
@@ -3,6 +3,10 @@ let singleCharMode = true;
 let simulationStepDuration = 500;
 
 function simulate(word) {
+    if(activeDocument !== null) {
+        return false;
+    }
+
     let steps = [];
 
     if (singleCharMode) {
@@ -16,7 +20,7 @@ function simulate(word) {
     });
     simulationStates.splice();
 
-    const startConnections = connections.filter(conn => conn instanceof StartConnection);
+    const startConnections = documents[activeDocument].connections.filter(conn => conn instanceof StartConnection);
     startConnections.forEach(connection => animations.push(new ConnectionAnimation(connection)));
     simulationStates = startConnections.map(conn => conn.state);
 
@@ -78,7 +82,9 @@ function simulationStep(input) {
 }
 
 function getOutgoingConnections(state) {
-    return connections.filter(connection => connection instanceof SelfConnection ? connection.state === state : connection.stateA === state);
+    if(activeDocument === null)
+        return [];
+    return documents[activeDocument].connections.filter(connection => connection instanceof SelfConnection ? connection.state === state : connection.stateA === state);
 }
 
 class ConnectionAnimation {