how to find gridview hidden label value from javascript

Is you really need this, make sure that only change GridView1 to your GridView Id

var c = document.getElementsByTagName("table");
        for (var i = 0; i < c.length; i++) {
            if (c[i].id.indexOf("GridView1") > -1) {
                var hidd = c[i].getElementsByTagName("input");
                for (var j = 0; j < hidd.length; j++) {
                    if (hidd[j].type == "hidden")
                        alert(hidd[j].id);
                }
            }
        }