It's not clear from Shadow DOM specification should or should not form elements in ShadowDOM be submitted durint the form submit. Spec reads (https://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/shadow/index.html#html-forms): 'Because the form's ownerDocument is the shadow host's document, the form submission must continue to work as specified.'. Does it mean that if the form contains Shadow tree all form elements in the tree should be submitted when the form is submitted? The current Shadow DOM implementation in Google Chrome does not submit these elements. If this is a bug then I'll file a bug for the implementation. But anyway specification should more clearly specify should or should not form submit affect elements in shadow trees.