https_transit.js

/**
 * A script for transitioning to HTTPS for clients that support it.
 * 
 * This script will make a request to https:yourdomain.com/ping?_clb_=? 
 * from the loaded http: document.
 * If the request is successful, it will convert all the internal links
 * to https:
 */
    jQuery(function ($) {
        if(location.protocol === 'http:') {
            // Check for HTTPS support
            setTimeout(function () {
                var host = location.host
                ,   proto = 'https:'
                ,   url = proto + '//' + host + '/ping?_clb_=?'
                ;
                $.getJSON(url).done(function (x) {
                    // If HTTPS is supported, switch all internal links to https:
                    if(x && (x.ok || x.ts)) {
                        $('a[href]')
                            .each(function (i,a) {
                                if(a.host == host) {
                                    a.protocol = proto;
                                }
                            })
                        ;
                    }
                })
            }, 1e2);
        }
    });