How to let Html Link (anchor) do a postback to be like LinkButton?

By default, controls use __doPostBack to do the postback to the server. __doPostBack takes the UniqueID of the control (or in HTML, the name property of the HTML element). The second parameter is the name of the command to fire.

So for a custom button, render to the output stream:

<a id="someclientid" name="someuniqueid" href="javascript:void(0);" onclick="__doPostBack('someuniqueid', '');">val</a>

In your custom button, add the IPostBackEventHandler, and this __doPostBack statement will fire its RaisePostBackEvent method automatically for you.

Use a server side html control, HtmlAnchor which is a server side a tag.

<asp:HtmlAnchor runat="server" onclick="RunServerSideMethod">Just a simple link</asp:HtmlAnchor>