var body = document.getElementsByTagName("body")[0];
var current_classes = body.className.split(/\s/g);
var new_classes = [];

for (var i = 0; i < current_classes.length; i++)
    if (current_classes[i] != 'noscript')
        new_classes.push(current_classes[i]);

new_classes.push("script");
new_classes.push("dom-state-loading");

body.className = new_classes.join(" ");