Read Configuration Settings of Web.config using Javascript

In Default.aspx (Head Section)
.....Javascript......
function ReadConfigSettings()
{
var conn = '<%=ConfigurationManager.ConnectionStrings["MyConnString"].ConnectionString %>'
alert(conn);
}
....end of javascript.....
Call this function on a button click and display the values of the configuration settings
Place a button in youe wrbpage and on OnClientClick call the function