diff --git a/src/common.js b/src/common.js
index 276a16b70d..214ace4189 100644
--- a/src/common.js
+++ b/src/common.js
@@ -1176,6 +1176,9 @@
                 name = value;
                 value = '';
             }
+            if (name === undefined || name === null) {
+                name = '';
+            }
             var field;
             if (!(name.toLowerCase() in this.strings) &&
                     !(name in this.fields)) {
diff --git a/tests/sao.js b/tests/sao.js
index 90b61cbf41..41c12a748a 100644
--- a/tests/sao.js
+++ b/tests/sao.js
@@ -2109,6 +2109,30 @@
 
     });
 
+    QUnit.test('DomainParser.completion', function() {
+        var compare = Sao.common.compare;
+        var parser = new Sao.common.DomainParser({
+            'name': {
+                'string': 'Name',
+                'name': 'name',
+                'type': 'char'
+            }
+        });
+
+        [
+        ['Nam', ["Name: "]],
+        ['Name:', ['Name: ']],
+        ['Name: foo', []],
+        ['Name: !=', []],
+        ['Name: !=foo', []],
+        ].forEach(function(test) {
+            var value = test[0];
+            var expected = test[1];
+            QUnit.ok(compare(parser.completion(value), expected),
+                'completion(' + value + ')');
+        });
+    });
+
         /*
     QUnit.test('CRUD', function() {
         var run_tests = function() {