avalon js implements imitating Weibo drag image sorting_javascript skills

<div id='wrap' ms-controller='drag_sort' class='ms-controller'>
 <ul ms-mousemove='drag_move($event)'>
 <li ms-repeat='photo_list'>
 <div ms-mousedown='start_drag($event,$index,el)'>
  <div class="dummy"></div>
  <p ms-attr-id='wrap_img{{$index}}'><img ms-attr-src="el.src"><i></i></p>
 </div>
 </li>
 </ul>
 <div id='drag_proxy'></div>
 </div>

 start_drag:function(e,i,el){
 var img=$('wrap_img'+i).firstChild,target_img_width=img.clientWidth,target_img_height=img.clientHeight;
 drag_sort.cell_size=$('wrap_img0').clientWidth;
 var xx=e.clientX-target_img_width/2,yy=e.clientY-target_img_height/2,offset=avalon($(drag_sort.container)).offset(),target=e.target.parentNode.parentNode.parentNode; 
 $('drag_proxy').style.top=yy+avalon(window).scrollTop()-offset.top+'px';
 $('drag_proxy').style.left=xx-offset.left+'px';
 $('drag_proxy').style.width=target_img_width+'px';
 $('drag_proxy').style.height=target_img_height+'px';
 if(target&&target.nodeName=='LI'){
  ori_src=el;
  // $('drag_proxy').innerHTML=target.querySelector('p').innerHTML;
  $('drag_proxy').innerHTML=$('wrap_img'+i).innerHTML;
  $('drag_proxy').style.display='block';
  drag_sort.target_index=i;
  drag_flag=true;
 }
 if(isIE)
  target.setCapture();
 avalon.bind(document,'mouseup',function(){
  up(target);
 });
 e.stopPropagation();
 e.preventDefault();
 }

drag_move:function(e){
 if(drag_flag){
  var xx=e.clientX,yy=e.clientY,offset=avalon($(drag_sort.container)).offset();
  var x=xx-offset.left,y=avalon(window).scrollTop()+yy-offset.top;
  var x_index=Math.floor(x/drag_sort.cell_size),y_index=Math.floor(y/drag_sort.cell_size),move_to=3*y_index+x_index;
  $('drag_proxy').style.top=y-drag_sort.cell_size/2+'px';
  $('drag_proxy').style.left=x-drag_sort.cell_size/2+'px';
  if(move_to!=drag_sort.target_index){
  drag_sort.photo_list.removeAt(drag_sort.target_index);
  drag_sort.photo_list.splice(move_to,0,{src:'1.jpg'});
  drag_sort.target_index=move_to;
  }
 }
 e.stopPropagation();
 }

#wrap{
 position: relative;
 max-width: 620px;
 font-size: 0;
 }
 #drag_proxy{
 position: absolute;
 border:1px solid #009be3;
 z-index: 100;
 display: none;
 }

function up(target){
 if(isIE)
 target.releaseCapture();
 var target_index=drag_sort.target_index;
 if(ori_src&&target_index!=-1){
 drag_sort.photo_list.splice(target_index,1);
 drag_sort.photo_list.splice(target_index,0,ori_src);
 }
 drag_holder=null;
 drag_flag=false;
 drag_sort.target_index=-1;
 $('drag_proxy').style.display='none';
 avalon.unbind(document,'mouseup');
 }

<div id='post_img' ms-controller='post_img'>
<ul id='post_img_inner' ms-mousemove='onmousemove'>
<li ms-repeat-el="post_img_list" class='inline-block' ms-mousedown='onmousedown($event,$index,el)' ms-attr-id='post_img_item{{$index}}'>
<img ms-src='el' class='uploaded_img'></li>
</ul>
</div>

var drag_holder=null,index=-1,ori_src=null,drag_flag=false;//拖动的代理，原图片，原图片的src
var post_img = avalon.define('post_img', function(vm) {
vm.post_img_list=[];//保存所有图片的src
vm.onmousedown=function(e,i,el){
$('drag_proxy').style.display='block';
var target=e.target.parentNode;
var xx = e.clientX;
var yy = e.clientY;
$('drag_proxy').style.top=yy+'px';
$('drag_proxy').style.left=xx+'px';
if(target&&target.nodeName=='LI'){
ori_src=el;
index=target.getAttribute('id').substring(13);
$('drag_proxy').innerHTML=target.innerHTML;
post_img.post_img_list.splice(i, 1, 'about:blank');
}
drag_flag=true;
};
vm.onmousemove=function(e){
if(drag_flag){//如果点下了图片
var xx = e.clientX;
var yy = e.clientY;
$('drag_proxy').style.top=yy+'px';
$('drag_proxy').style.left=xx+'px';
var x=xx-avalon($('post_img')).offset().left;
var y=yy-avalon($('post_img')).offset().top;
//例子没有考虑滚动条的情况
var x_index=Math.floor(x/100);//图片尺寸100*100
var y_index=Math.floor(y/100);
post_img.post_img_list.splice(index, 1);//删除当前图片的li
var target_index=3*y_index+x_index;//目标图片的位置（3*3）
if(post_img.post_img_list.indexOf('about:blank')!=target_index)
//如果图片数组中没有src=about:blank这个占位置的li
post_img.post_img_list.splice(target_index, 0, 'about:blank');
//添加src=about:blank
index=target_index;
//会触发很多次move,所以触发一次就改动一次
}
};
});
document.onmouseup=function(e){
drag_holder=null;
if(ori_src){
post_img.post_img_list.splice(index, 1);
//删除src=about:blank
post_img.post_img_list.splice(index, 0,ori_src);
//添加原图片
}
$('drag_proxy').style.display='none';
$('drag_proxy').innerHTML='';
drag_flag=false;
};