ASP.NET 4.5, ImageButton OnClick not firing on MasterPage -

i have imagebutton in masterpage , it's not firing onclick event. in pages without masterpage works.

http://www.quotehd.com/default.aspx not have masterpage , if enter word 'funny' in search works, if try search http://www.quotehd.com/topics uses masterpage not fire code masterpage.

this masterpage aspx code:

<asp:imagebutton id="lnkgo1" runat="server" cssclass="searchsubmit"       imageurl ="/content/themes/pin/images/search.png" onclick="lnkgo1_click"       causesvalidation="false" viewstatemode="disabled" enableviewstate="false">   </asp:imagebutton>                                        

c# masterpage code:

protected void lnkgo1_click(object sender, imageclickeventargs e) {    response.redirect("~/quotes/search/words/" + httputility.htmlencode(txtsearch1.text)); } 

the same code works on /default.aspx not have masterpage, if access homepage default.aspx

i have added line masterpage onload , works.

form1.action = request.url.pathandquery;