diff --git a/dlls/jscript/jsstr.c b/dlls/jscript/jsstr.c
index aad7af29cc4..d34af0feae5 100644
--- a/dlls/jscript/jsstr.c
+++ b/dlls/jscript/jsstr.c
@@ -72,16 +72,19 @@ jsstr_t *jsstr_concat(jsstr_t *str1, jsstr_t *str2)
     jsstr_t *ret;
 
     len1 = jsstr_length(str1);
+    if(!len1)
+        return jsstr_addref(str2);
+
     len2 = jsstr_length(str2);
+    if(!len2)
+        return jsstr_addref(str1);
 
     ret = jsstr_alloc_buf(len1+len2);
     if(!ret)
         return NULL;
 
-    if(len1)
-        memcpy(ret->str, str1->str, len1*sizeof(WCHAR));
-    if(len2)
-        memcpy(ret->str+len1, str2->str, len2*sizeof(WCHAR));
+    memcpy(ret->str, str1->str, len1*sizeof(WCHAR));
+    memcpy(ret->str+len1, str2->str, len2*sizeof(WCHAR));
     return ret;
 }