gistfile1.js

/**
*
*    Don't break scale on iPad rotate.
*
*    By default iPad re-zooms the page when the device orientation changes.
*
*    The heuristics here do not work always; our page got zoomed in
*    though it should be max zoomed out.
*
*    This snippet fixes the situation so that you can still zoom in, but when
*    the device is rotated the scale is restored.
*
*/

(function(doc) {
    'use strict';

    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 = [0.25, 1.6];
        doc[addEvent](type, fix, true);
    }

}(document));