diff --git a/lib/gtk.js b/lib/gtk.js
index 8e0d330..66d3a64 100644
--- a/lib/gtk.js
+++ b/lib/gtk.js
@@ -16,11 +16,57 @@ var GTKWidgets = {};
 var GTKWidget = function() {
     this.widgetType = "GTKWidget";
     this.widgetID = GTKCreateWidget(this);
-    this.onEventTriggered = function() {};
+
+    this.eventListener = GTKEventListener(this);
+    this.addEventListener = function(ev, fn) {
+        if (typeof(fn) == "function") {
+            this['on' + ev] = fn;
+        } else {
+            throw new TypeError("EventListener must be a function");
+        }
+    };
 
     GTKWidgets[this.widgetID] = this;
 };
 
+// definedEvents
+var definedEvents = {
+    "Window" [
+        "onload"
+    ],
+    "Table": [
+        "onload"
+    ],
+    "Button": [
+        "onload",
+        "onclick"
+    ],
+    "Entry": [
+        "onload",
+        "onkeyup"
+    ]
+    "RadioBox": [
+        "onload",
+        "onclick"
+    ],
+    "TextBox" [
+        "onload"
+    ]
+};
+
+// GTKEventListener
+var GTKEventListener = function(widget) {
+    if (widget.widgetType in definedEvents) {
+        var widgetEvents = definedEvents[widget.widgetType];
+        for (var i = 0; i < widgetEvents.length; i++) {
+            var eventName = widgetEvents[i];
+            if (eventName in widget && typeof(widget[eventName]) == "function") {
+                widget[eventName]();
+            }
+        }
+    }
+};
+
 // GTKCreateElement
 var GTKCreateWidget = function(widget) {
     var widgetID, commands = [];
@@ -269,7 +315,7 @@ var GTKWait = function(callback) {
         ]);
 
         if (even in GTKWidgets) {
-            GTKWidgets[even].onEventTriggered();
+            GTKWidgets[even].eventListener();
         }
 
         if (typeof(callback) == "function") {