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@bobslaede
Created September 16, 2011 08:50
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Modernizr position fixed check
;(function(Modernizr, window) {
Modernizr.addTest('positionfixed', function () {
var test = document.createElement('div'),
control = test.cloneNode(false),
fake = false,
root = document.body || (function () {
fake = true;
return document.documentElement.appendChild(document.createElement('body'));
}());
var oldCssText = root.style.cssText;
root.style.cssText = 'padding:0;margin:0';
test.style.cssText = 'position:fixed;top:42px';
root.appendChild(test);
root.appendChild(control);
var ret = test.offsetTop !== control.offsetTop;
root.removeChild(test);
root.removeChild(control);
root.style.cssText = oldCssText;
if (fake) {
document.documentElement.removeChild(root);
}
return ret;
});
Modernizr.addTest('iospositionfixed', function () {
var test = document.createElement('div'),
ret,
fake = false,
root = document.body || (function () {
fake = true;
return document.documentElement.appendChild(document.createElement('body'));
}());
if (typeof document.body.scrollIntoViewIfNeeded === 'function') {
var oldCssText = root.style.cssText,
testScrollTop = 20,
originalScrollTop = window.pageYOffset;
root.appendChild(test);
test.style.cssText = 'position:fixed;top:0px;height:10px;';
root.style.height="3000px";
/* avoided hoisting for clarity */
var testScroll = function() {
if (ret === undefined) {
test.scrollIntoViewIfNeeded();
if (window.pageYOffset === testScrollTop) {
ret = true;
} else {
ret = false;
}
}
window.removeEventListener('scroll', testScroll, false);
}
window.addEventListener('scroll', testScrollTop, false);
window.setTimeout(testScroll, 20); // ios 4 does'nt publish the scroll event on scrollto
window.scrollTo(0, testScrollTop);
testScroll();
root.removeChild(test);
root.style.cssText = oldCssText;
window.scrollTo(0, originalScrollTop);
} else {
ret = Modernizr.positionfixed; // firefox and IE doesnt have document.body.scrollIntoViewIfNeeded, so we test with the original modernizr test
}
if (fake) {
document.documentElement.removeChild(root);
}
return ret;
});
})(Modernizr, window);
@WebStew
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WebStew commented Apr 24, 2017

Hi @jtangelder.

It's worth noting that it looks as though with the recent release of OS 10 the UA string will match the regex ua.match(/(iphone|ipad|ipod).+(OS [0-4])/i) eg iPhone OS 10_3_1

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