Open mail to page when click on ASP.NET image

Hello,
I try to click on company logo to open the default company page and email icon should be open mail to page. Here are my following code but they are not working. 
<div class="header">      <asp:ImageButton ID="imgBtnLogo" runat="server" ImageUrl="~/Images/logo.png" OnClientClick="window.open('https://www.uaminc.com')" />       <asp:ImageButton ID="imgBtnEmail" runat="server" ImageUrl="~/Images/email.png" OnClientClick="javascript:window.open('mailto:mail@domain.com', 'Mail')"/> </div>
There were an error on second code line. Please let me know what wrong? Thanks.