[рони]

RapCore,

$(function() {
    function b(a) {
        "mousemove" == a.type && (c = +a.clientY);
        50 > c && "mouseleave" == a.type && ($(document).off("mouseleave mousemove", b), alert("stop"))
    }
    var c = 100;
    $(document).on("mouseleave mousemove", b)
});