Slider is not working broken logic javascript

Question

I am trying to make a slider. But for some reason i can't get the logic right. I know once in past i have gotten it right. But i don't remember it now.

Updated http://jsfiddle.net/techsin/9QqNa/2/

var slider= $('.slider'), mY, dY, clicking=false;

slider.mousedown(function(e){
     mY = e.pageY, clicking = true;
})
$(window).mousemove(function(e){
    if (!clicking) return;
    e.preventDefault();
    dY= e.offsetY-mY;
    mY +=dY;
    console.log(e);
    slider.css('top','+='+dY);
}).mouseup(removeit);

function removeit(){ 
    clicking=false; 
}

Problems Include: Updated - Need to stop at above and bottom limits.

Answer 1

Just had a quick look at your code, simply change the follow line:

dY= e.offsetY-mY;

to

dY= e.pageY-mY;

this should do