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Improved version of JavaScript fix for the iOS viewport scaling bug. See http://www.blog.highub.com/mobile-2/a-fix-for-iphone-viewport-scale-bug/
// Original code from http://www.blog.highub.com/mobile-2/a-fix-for-iphone-viewport-scale-bug/
var metas = document.getElementsByTagName('meta');
var i;
if (navigator.userAgent.match(/iPhone/i)) {
for (i=0; i<metas.length; i++) {
if (metas[i].name == "viewport") {
metas[i].content = "width=device-width, minimum-scale=1.0, maximum-scale=1.0";
}
}
document.getElementsByTagName('body')[0].addEventListener("gesturestart", gestureStart, false);
}
function gestureStart() {
for (i=0; i<metas.length; i++) {
if (metas[i].name == "viewport") {
metas[i].content = "width=device-width, minimum-scale=0.25, maximum-scale=1.6";
}
}
}
// Rewritten version
// By @mathias, @cheeaun and @jdalton
(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);
}
}(document));
@ddantes
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ddantes commented Jul 12, 2013

I appreciate this code, which has helped me as I've adapted my website to be more mobile friendly. I'm posting about an issue which just came to my attention, hoping for some advice. It seems that the bug fix doesn't work if a page includes dynamic text. I have two pages which implement the bug fix, although the script is external in a file named MaintainViewport.js. If you visit http://mauitradewinds.com/test/view.htm you will see a horizontally-scrolling image with a fixed text caption. The viewport bug fix works perfectly. But, at http://mauitradewinds.com/test/test.htm there is a fading caption below the scrolling image. The viewport bug is not fixed on this page, although it references the same javascript to correct that bug. If I remove the dynamic caption, the viewport bug also disappears. If there is a solution to this, I'd be grateful to see it.

@highruned
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}(document));? should be })(document);

@enure
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enure commented Feb 10, 2014

@ericmuyser - you can write it either way. The latter is more common, but the former works as well.

@jpblancoder
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You might want to update with additional meta params, for iOS 6+.

function fix() {
        meta.content = 'width=device-width, initial-scale=1.0, maximum-scale=' + scales[1] + ', user-scalable=no, minimum-scale=' + scales[0];
        doc.removeEventListener(type, fix, true);
    }

@DaveFlash
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hmm, still seems to create problems for me....

@HarroH
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HarroH commented Aug 11, 2017

Is this fix still applicable to iOS or has Apple solved this issue?

@webaffin
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Is this fix still applicable to iOS or has Apple solved this issue?

I also want to know...

@GraniteConsultingReviews

I tested this code and its working well. thanks for sharing.

@MattShaile
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I don't think this works any more (iOS 10+) due to Apple now ignoring the scale meta tags

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