$(document).ready(function(){
    animateM();
});
function newPosition(){
    var h = $(window).height() - 50;
    var w = $(window).width() - 50;
    var nh = Math.floor(Math.random() * h);
    var nw = Math.floor(Math.random() * w);
    return [nh,nw];
}
function animateM(){
    var newq =  newPosition();
    $('.animateM').animate({ top: newq[0], left: newq[1] }, function(){
        animateM();
    });
};

setTimeout(function() {
    $('.animateM').animate({
        top: newq[0],
        left: newq[1],
    }, 750);
, 2000 ); // 2000 is duration