Client script inside C#

$(document).ready(function() {";
st += " if(" + sales_tot_qty.ToString() + "==" + selected_qty.ToString() + ")";
st += " {";
st += " $('#tabs').tabs('enable',1);";
st += " }";
st += " else";
st += " {";
st += " $('#tabs').tabs('disable',1);";
st += " }";
st += "});";
st += "";

Page.ClientScript.RegisterStartupScript(typeof(string), "tabswitch", st);