hello.onmousedown = function(e){
    tion(e);
}
ball.onmousedown = function(e){
    tion(e);
}

function tion(e) {
    var elem = e.target;

    if(elem.className == "screen"){
        //code 
    }

    if(elem.className && elem.className.indexOf('bob')>=0) { 
        elem.ondragstart = function() {return false}; 
        var coor = elem.getBoundingClientRect(); 
        var osx = e.offsetX; 
        var osy = e.offsetY; 
        elem.style.position = 'fixed';
        elem.style.top = coor.top+'px'; 
        elem.style.left = coor.left+'px'; 

        document.onmousemove = function(ev){
            var x = ev.clientX;
            var y = ev.clientY; 
            var winX = document.documentElement.clientWidth; 
            var winY = document.documentElement.clientHeight;
            if (x+coor.width>winX+osx) {x=winX-coor.width+osx}; 
            if (x-osx<0) {x=osx};
            if (y<=osy) { 
                y = osy; 
            };
            if (y>=(winY-coor.height+osy)) {  
                y=winY-coor.hieght-osy; 
            }
            elem.style.left = x-osx+'px'; 
            elem.style.top = y-osy+'px'; 
            removeSelect(); 
        }
    }

} //закрывает tion

document.onmouseup = function(e) { 
    var elem = e.target; 
    if (elem.className && elem.className.indexOf('bob')>=0) {
    go(elem);
    }
    document.onmousemove = function() {return false};
}

function removeSelect() { 
    var b =document.body; 
    b.style.webkitUserSelect = b.style.mozUserSelect = b.style.msUserSelect = 'none'; 
};

function getCoords(element) {
  var box = element.getBoundingClientRect();
  return {
      left: pageXOffset + box.left,
      top: pageYOffset + box.top
  }
};

thumb.ondragstart = function(e) {
  return false;
};

function go(elem){
    var W = document.documentElement.clientHeight - 40 + 'px';
    $(elem).animate({top:W});
}