jQuery DataTables排序不起作用

Using jQuery 2.1.3 and DataTables 1.10.5, my table won't sort when I click on the up- and down-arrows above the columns. From what I can tell from the documentation, this is the simplest example, and should work. I can't seem to figure out why it isn't.Using jQuery 2.1.3 and DataTables 1.10.5, my ta