how check whether the link button was being clicked

hi, how to check whether a link button was being clicked or not ? thanks
my.aspx  =====================================
<asp:TemplateField>      
  <ItemTemplate>            
<asp:ImageButton ID="ImageButton1" runat="server" Visible="false" OnClientClick="javascript: test(this);"  src="../scripts/img/32 (37).png"/>                                                            
  </ItemTemplate>        
</asp:TemplateField>
...