How to disable back button on checkout page

Our payment provider requires us to disable browsers back button from the moment the customer is being redirected from our website to their payment menu.
(to prevent the creation of multiple payment ID's in their system)

We are using one page checkout, so I need to disable back button on CheckoutOnepage.aspx. (please correct me if I am wrong)

I tried to add the following script in code behind:

        protected override void OnPreRender(EventArgs e)
        {
            base.OnPreRender(e);
            string strDisAbleBackButton;
            strDisAbleBackButton = "<script language=\"javascript\">window.history.forward(1);</script>";

            ClientScript.RegisterClientScriptBlock(this.Page.GetType(), "clientScript", strDisAbleBackButton);
        }

However, it didn't work.

What should I do to disable back button on checkout page?