nearest（）是上树，进入父母，包括当前元素。 find（）正在向下查看孩子的树，以及孩子的孩子：

closest() is to go up the tree, into the parents, including the current element. find() is going down the tree looking in the childs, and the childs of childs:

var form1 = $("input").closest("form").attr("action");