ok, I have your solution. First use below in .aspx page
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" MaintainScrollPositionOnPostback="true"%>
now after that put below code in code behind file
protected void Page_Load(object sender, EventArgs e)
{
SmartNavigation = true;
}
now create a default folder of App_Browsers in root directory and add new item, select browser.browser file and set its name like SafariFix.browser and put replace below code
<browsers>
<browser id="NewBrowser" parentID="Mozilla">
<identification>
<userAgent match="Unique User Agent Regular Expression" />
</identification>
<capture>
<userAgent match="NewBrowser (?'version'\d+\.\d+)" />
</capture>
<capabilities>
<capability name="browser" value="My New Browser" />
<capability name="version" value="${version}" />
</capabilities>
</browser>
<browser refID="Safari1Plus">
<capabilities>
<capability name="supportsMaintainScrollPositionOnPostback" value="true" />
</capabilities>
</browser>
</browsers>
it will completely solve your problem, because i already tested in all three browsers