In SharePoint document library there is an option in action menu i.e “open in Windows Explorer”,When we click this one we can see all the documents in a window explorer,where we can drag and drop the documents for the document library .

But in case of a SharePoint generic list we don’t have this option.To implement this functionality we need to add the following script in the page, and call the script method from a event. In SharePoint list, if a list Item contains any attachment, it creates a folder with the name of the item id and add the attachments inside that  folder. When we open the list in Window Explorer we can see the folders for the list items which contain attachments, here we can drag and drop the documents to save as attachment for the list Item.

<style>
       .httpFolder {behavior: url(#default#httpFolder);}
</style>
<script>
       function fnOpenFolderView() {
        oDAV.navigateFrame("url for the list", "_self");
         }
</script>
     
<div id = "oDAV" class = "httpFolder"/>
 
   <!-- The input object calls the fnOpenFolderView function -->
 <input type = "button" value = "Open Folder View" onclick ="fnOpenFolderView()"/>