Fetching data from gridview textbox using javascript

i have a gridview.
there is a itemtemplet a TEXTBOX  txt_name
i want to fetch this textbox text using javascript.
how can i do this.
how can i call that textbox of gridview using javascript

Find the text box on Row data bound event and try applying the javascript attribute for that some thing like

txt.attributes.add("function(ex:onclick")","your JS function");

I am not sure about this but make a try

This works for me

 protected void gvDetails_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            TextBox txt = (TextBox)e.Row.FindControl("txt");
            txt.Attributes.Add("onclick", "f1()");
        }
    }

I just write a simple javascript to alert hello in that f1()

 <script type="text/javascript">
        function f1() {
            alert('Hello');
        }
    </script>

alternative you can pass the control to function if needed