how would I detect if “multiple” attribute is supported for file input elements?

Question

Internet Explorer does not support the multiple attribute for . However, its not only IE that lacks this support... al

Answer 1

var inp = document.createElement("input");
inp.setAttribute("multiple", "true");
var supportsMultiple = inp.multiple===true;

Answer 2

You can try checking for the existence of the corresponding property:

var supportsMultipleFiles = 'multiple' in document.createElement('input');

Example: http://jsfiddle.net/sbZvS/