how to have an action happen only one time

how to have an action happen only one time

hello,
for example if i have the following action:
when i hover into a div the background fades out, when i hover out the background fades back in. if you hover in - out multiple times , everything will happen multiple times, how can you tell jquery to have an event only happening one time (then when you refresh the page or something(pretty sure is the refresh wich guide this in the internal of Js), so when you refresh the page the event acts again
regards