Below is a (very) simple example:

// This is the callback
function processResponse(rcvd)
{
var jsonObj = JSON.parse(rcvd);
// Response to a successful http runevent request is:
// {"Response":"ok"}
// Note: actual response depends on HomeSeer JSON request (see HomeSeer doc)
var jsonObj = JSON.parse(rcvd);
if (jsonObj.Response == "ok") {
// Success!...
} else {
// Failure...
}
}