js实现鼠标跟随运动效果

$("#cursorPlay li").on("mouseenter mouseleave",function(event){
var evType = event.type;
var direction = getDir($(this), {
x: event.pageX,
y: event.pageY
});
// console.log("evtype:"+evType+",dir:"+direction);
moveTo($(this),direction, evType);
});
2、

direction = Math.round((((Math.atan2(y, x)  (180 / Math.PI)) + 180) / 90) + 3) % 4;
function getDir($el, coordinates){
var w = $el.width(),
h = $el.height(),
x = (coordinates.x - $el.offset().left - (w / 2))  (w > h ? (h / w) : 1),
y = (coordinates.y - $el.offset(). - (h / 2))  (h > w ? (w / h) : 1),
direction = Math.round((((Math.atan2(y, x)  (180 / Math.PI)) + 180) / 90) + 3) % 4;
return direction;
}

function moveTo($el, direction, type){
 var $layer = $el.find("div");
 var coord = {};
 if(type === "mouseenter"){
  switch(direction){
   case 0 :  $layer.css("","-100%").css("left","0px");break;
  case 1 : $layer.css("left","100%").css("","0px");break;
  case 2 : $layer.css("","100%").css("left","0px");break;
  case 3 : $layer.css("left","-100%").css("","0px");break;
 }
  coord = {left:0,:0}
 }else{
 switch(direction){
  case 0 : coord = {left:0,:'-100%'};break;
  case 1 : coord = {left:'100%',:0};break;
  case 2 : coord = {left:0,:'100%'};break;
  case 3 : coord = {left:'-100%',:0};break;
 }
}
$layer.animate(coord,300);
}