c Background modifies the sample code for the css property of foreground DOM

< div id = 'div1' runat="server" > haha < /div >
-----------
This is called in the background code

div1.Style["display"]="inline";

Note that double quotes are used in c#.

using System. Web. UI. WebControls; You have to introduce this namespace

Style["background-image"]
= "url (images/bg_active jpg)"; , etc.