load.js

(function () {
  
    var soak = function () {

        // a list of URLs to test
        var urls = [
            'http://next.ft.com/uk' // TOOD - mappings between ft & next
        ];

        urls.forEach(function (url) { console.log(url);
            $.ajax({
                url: url, 
                method: 'GET',
                crossDomain: true,  // www.ft -> next.ft
                headers: {                 
                    'x-next-ftcom-soak': 'true' // will need to configure Vannish to let these users through
                }
            })
        });
    };

    // don't do this if we are on an old browser
    if (!Array.prototype.forEach) {
        return;
    }

    // only run for 5% of traffic
    if (Math.random() > 0.05) {
        return;
    }
    
    setTimeout(soak, 5000);

})()