I have a web page that drags element from div and drop them to another div.
for each dropped item in the drop div, when the user clicks on the element its open a dialog to insert entry and then save it.
How to insert small icon to the dropped element that indicate that this element have data (alert icon).
provided that we have multiple elements to drag and drop.
From your description, if you want to insert a small icon into a div, I suppose you should drag an image control to the div. Then, use the image control to appear the icon. You
could refer to the following code:
<img src="pic_mountain.jpg" alt="Mountain View" style="width:50px;height:50px">
<asp:Image runat="server" ImageUrl="/banners/w6.gif"/>
Besides, I suppose perhaps you want to use alert box. If that is the case, you could use the following code:
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" OnClientClick="return confirm('Do you want to Submit?');" Text="Button" /><br />
and here are also have some JQuery plugins, perhaps they can help you.