Chinese for "vote-up", "vote-down" and "vote to close"
Usually you would use:

(投)赞成(票)   Vote-up

(投)反对(票)   Vote-down

投关闭票       Vote to close

However, when used on internet, especially sites like SE, probably the following is more suitable:

顶 - literally means bump  (Vote-up)

踩 - literally means tread  (Vote-down)

叉 - literally means X (cross), have the implication of closing.  (Vote to close)