Prevent textbox autofill with previously entered values

For firefox

Either:

<asp:TextBox id="Textbox1" runat="server" autocomplete="off"></asp:TextBox>

Or from the CodeBehind:

Textbox1.Attributes.Add("autocomplete", "off");

Autocomplete need to set off from textbox

<asp:TextBox ID="TextBox1" runat="server" autocomplete="off"></asp:TextBox>

By making AutoCompleteType="Disabled",

    <asp:TextBox runat="server" ID="txt_userid" AutoCompleteType="Disabled"></asp:TextBox>  

By setting autocomplete="off",

    <asp:TextBox runat="server" ID="txt_userid" autocomplete="off"></asp:TextBox>  

By Setting Form autocomplete="off",

    <form id="form1" runat="server" autocomplete="off">  
    //your content  
    </form>  

By using code in .cs page,

    protected void Page_Load(object sender, EventArgs e)   
    {  
        if (!Page.IsPostBack)  
        {  
            txt_userid.Attributes.Add("autocomplete", "off");  
        }  
    }  

By Using Jquery

    <head runat = "server" >  
        < title > < /title> < script src = "Scripts/jquery-1.6.4.min.js" > < /script> < script type = "text/javascript" >  
        $(document).ready(function()  
        {  
            $('#txt_userid').attr('autocomplete', 'off');  
        });  
    //document.getElementById("txt_userid").autocomplete = "off"  
    < /script>  

and here is my textbox in ,

    <asp:TextBox runat="server" ID="txt_userid" ></asp:TextBox>  

By Setting textbox attribute in code,

    protected void Page_Load(object sender, EventArgs e)   
    {  
        if (!Page.IsPostBack)  
        {  
            txt_userid.Attributes.Add("autocomplete", "off");  
        }  
    }