scale.fix.js

fixScale = function(doc) {

var addEvent = 'addEventListener',
    type = 'gesturestart',
    qsa = 'querySelectorAll',
    scales = [1, 1],
    meta = qsa in doc ? doc[qsa]('meta[name=viewport]') : [];

    function fix() {
        meta.content = 'width=device-width,minimum-scale=' + scales[0] + ',maximum-scale=' + scales[1];
        doc.removeEventListener(type, fix, true);
    }

    if ((meta = meta[meta.length - 1]) && addEvent in doc) {
        fix();
        scales = [.25, 1.6];
        doc[addEvent](type, fix, true);
    }
};