jquery ajax readystate 0 responsetext status 0 statustext error

I was getting this error and in my case it was not due to same origin policy. I got some help from this link. Other possible reasons can be seen in here.

My case was, I had a link button and I was not using e.PreventDefault()

ASPX

<asp:LinkButton ID="lnkSearch" runat="server" CssClass="DockCmdSearch" CommandName="Search" OnClientClick="return VerifySearch(this, event);" />

Javascript

function VerifySearch(sender, e) {        
    e.preventDefault();
    $.ajax({
                type: 'POST',
    .............
    }
    return false;
}