I would do something like this;
var keyTimer;
j$132('#AdvanceSearch table:first input').keyup(function () {
if(keyTimer){
clearTimeout(keyTimer);
}
keyTimer = setTimeout(function () {
LoadAdvanceSearch();
}, 500);
});
It will clear the timeout each time if it has not fired yet. So then it will only run if the user stops typing for half a second.