[Dilettante_Pro]

Чето нету ошибки

<div id='treeview' style='width:300px; border:1px solid black'>qwertyuiopasdfgh</div>
<div id='addcontaineritem' style='border:1px solid black'>a</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(window).load(function(){ 
var item=$("#treeview").outerWidth(true);
 
$("#addcontaineritem").width(item);
 });
</script>