User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Firefox/45.0 Build ID: 20160407164938 Steps to reproduce: <html><head></head><body> <button> <div title="my title">aaaaa</div> </button> </body></html> Actual results: The tooltip for the div tag is never showed. Expected results: The tooltip shoud appear (like in chrome).
User Agent: Mozilla/5.0 (Windows NT 6.1; rv:45.0) Gecko/20100101 Firefox/45.0 Build ID: 20160407164938 I have tested your issue on latest FF release (45.0.2), latest Nightly build (20160424030601) and managed to reproduce it. I have created a .html file and pasted the code you provided. Firefox does not display the title of the page as Chrome does. IE has the same behavior as Firefox.
I think Chrome is correct, while IE and firefox fails. In w3c: https://www.w3.org/TR/2012/WD-html5-20121025/global-attributes.html#attr-title "If this attribute is omitted from an element, then it implies that the title attribute of the nearest ancestor HTML element with a title attribute set is also relevant to this element."
In IE11 the tooltip is showed correctly.