Web Forms :: How To Open Page In New Tab Using ImageButton OnClick Event

I have 1 image button and Linkbutton in my page below is code:

<asp:ImageButton ID="ImageButton2" runat="server" ImageUrl="~/image/editpro.png"
CssClass="DMPIMG" OnClick="ImageButton2_Click" OnClientClick="return ValidateRange()" />

and Linkbutton:

<asp:LinkButton ID="LinkproM" runat="server" CssClass="Links3" OnClick="LinkproM_Click"
CausesValidation="false">مدیریت محصولات</asp:LinkButton>

I want when I click on imagebutton it open page in new window so I wrote below code:

<script type="text/javascript">
function ValidateRange() {
document.forms[0].target = "_blank";
return true;
}
</script>

and I want when I click on linkbutton it doesn't open new window...

here when I click on linkbutton it doesn't  open new window it is correct but when I click on imagebutton and it opens new window and back to page and click on linkbutton it open linkbutton in new window...

I want when I click on link button it doesn't open new window any way...