How to avoid page refreshing after button click

I've this problem for 3 days and I couldn't find the real answer. I want that if I click a button the code will run and not to refresh all the page. For example:

ASPX code

<dx:ASPxButton ID="ASPxButton1" runat="server" Text="New" OnClick="ASPxButton1_Click"></dx:ASPxButton>
<dx:ASPxButton ID="ASPxButton2" runat="server" Text="Delete"></dx:ASPxButton>

CS code

protected void ASPxButton1_Click(object sender, EventArgs e) //new button
{
    ASPxButton2.Enabled = false;
}

That's basicly what I want to do. Click the new button and make the delete button enabled false without refreshing all the page.

What I tried:

<dx:ASPxButton ID="ASPxButton1" runat="server" Text="New" OnClick="ASPxButton1_Click" onclientClick=" return false;"></dx:ASPxButton>
<asp:button ID="Button1" runat="server" Text="New" OnClick="Button1_Click" onclientClick=" return false;"></asp:button>
<asp:button ID="Button1" runat="server" Text="New" OnClick="Button1_Click"></asp:button>
<asp:button ID="Button1" runat="server" Text="New" OnClientClick="DisableButton(); return false; "></asp:button>

function DisableButton() {
  document.getElementById("<%= ASPxButton2.ClientID %>").click();
}

Tried UpdatePanel too but I use MasterPage and that's why it doesn't work.