How detect my internet connection without using navigator

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ASP.NET

jQuery

Hi all,
I need to detect whether Internet connection is there when my script loads, i used navigator.online it says" connection is there " if the PC in LAN and able to connect to internet, and also the path to my Gmap js files should load according the connection settings online and offline settings intially i tried

$(document).ready(function () {
$.ajax({
url: 'http://in.yahoo.com/',
success: function (data) {
alert('Connection.');
},
error: function (data) {
alert('No Connection.');
}
});
});

but this is also not working.

iam getting error like XMLHttpRequest cannot load http://in.yahoo.com/. Origin http://localhost:40624 is not allowed by Access-Control-Allow-Origin.

For which i added

protected void Application_BeginRequest(object sender, EventArgs e)
{
HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");
}
in my Global.asax file

PLs suggest me i nearly spend a Day in searching,pls help me out