How to handle onchange event on input type=file in jQuery?

The code is:

<input ID="fileUpload1" runat="server" type="file"

The following works fine:

<input onchange="javascript:alert('hola');" ID="fileUpload1"  runat="server" type="file"

I'd like to get this result using jQuery, but that doesn't work:

$('#fileUpload1').change(function (e) {
    alert("hola");
});

I am missing something? (Edit: Yes I missed include the *.js file.)