How to write code behind for <a> tag

Question

I need to use a tag with click event and the href link I need to write it in code behind
when the link is clicked it will be opened on iframe by writing iframe id in the target of a tag

I tried the code below

please help

Thank you  

 

<a id="urlbb" runat="server" >web1
<asp:PlaceHolder ID="url" runat="server" Visible="false">
<iframe name="aa" width="100%" height="800px" style="margin-top:50px"></iframe></asp:PlaceHolder>
<asp:PlaceHolder ID="mainbody" runat="server" Visible="true">
.
.
.
.

</asp:PlaceHolder>
Code behind
protected void urlbb_ServerClick(object sender, EventArgs e)
{
mainbody.Visible = false;
url.Visible = true;
urlbb.Target = "aa";
urlbb.HRef = "http://www.bradford.ac.uk/it-services/students/email/";
}