syntax error in dropdown example causes error in Safari

[davidallenmann]

https://github.com/plotly/documentation/blob/source-design-merge/_posts/plotly_js/controls/callbacks-dropdowns/2015-11-19-simple-dropdown.html

Line 69 is missing square bracket and should be: var innerContainer = document.querySelector('[data-num="0"]'),

error behavior is that it does not run in Safari