fix observeInput logic

public/static/js/rvr.js

@@ -158,12 +158,17 @@ var RVR = {
         document.getElementById('cover').style.visibility = 'hidden';
     },
 
-    observeInput: function (input, buttonToToggle) {
-        if (input.defaultValue !== input.value) {
-            buttonToToggle.disabled = false;
-        } else {
-            buttonToToggle.disabled = true;
+    observeInput: function (form, observedInputs) {
+        var anyChanged = false;
+
+        for (var i = 0; i < observedInputs.length; i++) {
+            var input = form.elements[observedInputs[i]];
+            if (input.defaultValue !== input.value) {
+                anyChanged = true;
+            }
         }
+
+        form.elements.submit.disabled = !anyChanged;
     },
 
     observeInputsInForm: function (form, observedInputs) {
@@ -174,12 +179,12 @@ var RVR = {
                 case 'INPUT':
                 case 'TEXTAREA':
                     input.oninput = function () {
-                        RVR.observeInput(this, form.elements.submit);
+                        RVR.observeInput(form, observedInputs);
                     };
                     break;
                 case 'SELECT':
                     input.onchange = function () {
-                        RVR.observeInput(this, form.elements.submit);
+                        RVR.observeInput(form, observedInputs);
                     };
                     break;
             }