diff --git a/jael/lib/src/ast/conditional.dart b/jael/lib/src/ast/conditional.dart
index c3697d84..c54f6358 100644
--- a/jael/lib/src/ast/conditional.dart
+++ b/jael/lib/src/ast/conditional.dart
@@ -20,8 +20,12 @@ class Conditional extends Expression {
 
   @override
   compute(scope) {
-    return (condition.compute(scope) == true)
-        ? ifTrue.compute(scope)
-        : ifFalse.compute(scope);
+    var v = condition.compute(scope) as bool;
+
+    if (scope.resolve('!strict!')?.value == false) {
+      v = v == true;
+    }
+
+    return v ? ifTrue.compute(scope) : ifFalse.compute(scope);
   }
 }
diff --git a/jael/lib/src/ast/expression.dart b/jael/lib/src/ast/expression.dart
index 24b0e7b4..0e0f8147 100644
--- a/jael/lib/src/ast/expression.dart
+++ b/jael/lib/src/ast/expression.dart
@@ -22,6 +22,12 @@ class Negation extends Expression {
 
   @override
   compute(SymbolTable scope) {
-    return !(expression.compute(scope) == true);
+    var v = expression.compute(scope) as bool;
+
+    if (scope.resolve('!strict!')?.value == false) {
+      v = v == true;
+    }
+
+    return !v;
   }
 }
diff --git a/jael/test/render/custom_element_test.dart b/jael/test/render/custom_element_test.dart
new file mode 100644
index 00000000..6b2f6932
--- /dev/null
+++ b/jael/test/render/custom_element_test.dart
@@ -0,0 +1,25 @@
+import 'dart:math';
+import 'package:code_buffer/code_buffer.dart';
+import 'package:jael/jael.dart' as jael;
+import 'package:symbol_table/symbol_table.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('render into div', () {
+    var template = '''
+    <element name="square-root">
+      The square root of {{ n }} is {{ sqrt(n) }}.
+    </element>
+    <square-root n="16" />
+    ''';
+
+    var html = render(template, {'sqrt': sqrt});
+  });
+}
+
+String render(String template, [Map<String, dynamic> values]) {
+  var doc = jael.parseDocument(template, onError: (e) => throw e);
+  var buffer = new CodeBuffer();
+  const jael.Renderer().render(doc, buffer, new SymbolTable(values: values));
+  return buffer.toString();
+}
\ No newline at end of file