diff --git a/tools/build/build.py b/tools/build/build.py
index 6e837bce..da841598 100755
--- a/tools/build/build.py
+++ b/tools/build/build.py
@@ -97,6 +97,7 @@ def build_oxjs(downloads=False, geo=False):
             'Fallback.js', # FIXME: not clear if needed here
             'Math.js', # Ox.MAX_LATITUDE depends on Ox.sinh
             'Object.js', # Ox.typeOf depends on Ox.hasOwn
+            'String.js', # HTML.js depends on Ox.char
             'Type.js' # Ox.slice may depend on Ox.typeOf
         ]
     ]