diff --git a/src/main/resources/static/js/controllers.js b/src/main/resources/static/js/controllers.js
index e54902f..f676512 100644
--- a/src/main/resources/static/js/controllers.js
+++ b/src/main/resources/static/js/controllers.js
@@ -18,8 +18,6 @@ transactionControllers.controller('TransactionListCtrl', [ '$scope', '$location'
 		};
 		
 		if (typeof $scope.categories !== 'undefined') {
-			// TODO default-Kategorie sollte per Account einstellbar sein
-			console.log('DID IT!');
 			$scope.transaction.category = $scope.categories[0];
 		}
 		
@@ -60,12 +58,18 @@ transactionControllers.controller('TransactionListCtrl', [ '$scope', '$location'
 	
 	$scope.postTransaction = function() {
 		
+		var amount = $scope.transaction.amount.replace(',', '.');
+		
+		if (amount.charAt(0) !== '+' && amount.charAt(0) !== '-') {
+			amount = '-' + amount;
+		}
+		
 		// via Resource (might be moved into a service)
 		var Transaction = $resource('/transactions');
 
 		var newTransaction = new Transaction({
 			"account" : $scope.account._links.self.href,
-			"amount" : $scope.transaction.amount,
+			"amount" : amount,
 			"date" : $scope.transaction.date,
 			"description" : $scope.transaction.description,
 			"category" : $scope.transaction.category._links.self.href,
diff --git a/src/main/resources/static/partials/transaction-list.html b/src/main/resources/static/partials/transaction-list.html
index 02e7f78..ace1ef4 100644
--- a/src/main/resources/static/partials/transaction-list.html
+++ b/src/main/resources/static/partials/transaction-list.html
@@ -2,10 +2,11 @@
 	<div>
 		<div><select ng-model='account' ng-change='refreshList()' ng-options="account.name for account in accounts track by account.id"></select></div>
 		<div>
-			<form role="form" ng-submit="postTransaction()">
+			<form name="form" ng-submit="postTransaction()">
 				<div>
-					Betrag: <input ng-model='transaction.amount' type='number' step='0.01' />
+					Betrag: <input name="amount" ng-model='transaction.amount' type='text' required ng-pattern="/^[+-]?(?:\d+(?:[\.,]\d{0,2})?|[\.,]\d{1,2})$/" />
 				</div>
+				<span ng-show="form.amount.$error.pattern"">The value is not a valid value!</span>
 				<div>
 					Kategorie: <select ng-model='transaction.category' size='1'
 						ng-options="category.name for category in categories track by category._links.self.href">
@@ -18,7 +19,7 @@
 					Notiz: <input ng-model='transaction.description' type='text' size='20' />
 				</div>
 				<div>
-					<input type="submit" />
+					<input type="submit" ng-disabled="form.amount.$error.pattern" />
 				</div>
 			</form>