window.setInterval("keepAlive()", 60000);

function keepAlive() {
    var http = getKeepAliveHTTPObject();
    if (http) {
        http.onreadystatechange = function() { }
        http.open('POST', '/KeepAlive.ashx', true);
        http.setRequestHeader('Content-Length', '0');
        http.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        http.setRequestHeader('Connection', 'close');
        http.send('');
    }
}

function getKeepAliveHTTPObject() {
    var xmlhttp = false;
    /*@cc_on
    @if (@_jscript_version >= 5)
    try {
        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
        try {
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {
            xmlhttp = false;
        }
    }
    @else
				xmlhttp = false;
			@end
    @*/
    if (!xmlhttp && typeof XMLHttpRequest != 'undefined') {
        try {
            xmlhttp = new XMLHttpRequest();
        } catch (e) {
            xmlhttp = false;
        }
    }
    return xmlhttp;
}