Jquery move table row up or down or move X

I saw the example

but no idea how due to fresh to jquery, is that any way to remove "up" key when it reach to the top and remove "down" key when it is the bottom.

And also, I need have a input to move my certain row to another row, eg: row 1,2,3 and move r开发者_运维知识库ow 1 to 3 just input 3 and press submit and it move.

Is that any example or tutorial to teach how to do so? as newbie to Jquery, hope someone help me, thank you :)

could you use css formating with :first-child :last-child selectors and display:none for the up key:

tr:first-child a.up,
tr:last-child a.down {
  diplay: none;
}