[jQuery] How can I use "remote" option in asp.net

Hi, everybody
I have some questions for the "remote" option in asp.net page, If I
have some value need to be verified in order to make it is unique, for
example:
.....
.....
userName:{
required: true,
remote: "verify.aspx"
}
about the verify.aspx, I don't know how to output the result. I
appreciate you feedback.
thanks,