back button on browser caches instead of reloading entire page in asp web application

If Page.IsValid Then
               Dim dsCustInfo As DataSet = New DataSet()
               Dim dsDealerInfo As DataSet = New DataSet()
               Dim dsAsDealerInfo As DataSet = New DataSet()
               Dim dsVehicleInfo As DataSet = New DataSet()
               Dim dsOtherDetails As DataSet = New DataSet()
               InsertData()
               SendEmail()
               ScriptManager.RegisterStartupScript(Page, Page.GetType(), "scr", "closeLoading();", True)
               ClearAll()
               Session.Abandon()
               ViewState.Clear()
               Page.Response.Cache.SetCacheability(HttpCacheability.NoCache)
               '  ClientScript.RegisterStartupScript(Me.GetType(), "myalert", "Your information has been submitted successfully", True)
               Dim message As String = "alert('Your information has been submitted successfully.')"
               ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", message, True)
           Else
               Dim ms As String = "alert('Please enter required fields.')"
               ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", ms, True)
           End If

function Valid() {
        debugger;
        var totalRows = $("#<%=gdvLineItems.ClientID %> tr").length;
        if (totalRows != 0) {
            if (Page_ClientValidate("Required") == true) {
                //StartProgressBar()
                PrintPanel();
                blockUI();
                return true;

            }
            else {
                validateAndHighlight();
                alert("Please fill the Required fields");
                return false;
            }
        }
        else {
            alert("Please Add Line Items/ Tires");
            return false;
        }
    }