Quick and dirty scroll-to-top bookmarklet with easing.

scroll-to-top.js

// full-source version:

javascript:(function(win) {

var STEP_SIZE = 200; // px
var DELAY = 20;      // ms

var ease = function(scrollTop) {
    if (scrollTop <= STEP_SIZE) {
        win.scroll(0, 0);
        return;
    }

    var newSt = scrollTop - STEP_SIZE;
    win.scroll(0, newSt);
    win.setTimeout(function() {
        ease(newSt);
    }, DELAY);
};

win.setTimeout(function() {
    ease(win.pageYOffset);
}, DELAY);

})(window);

// bookmarklet version:

javascript:(function(a){var d=function(b){if(200>=b)a.scroll(0,0);else{var c=b-200;a.scroll(0,c);a.setTimeout(function(){d(c)},20)}};a.setTimeout(function(){d(a.pageYOffset)},20)})(window);