AntonLitvin/viewport.js

## viewport.js
/*
 * Paste into the end <head>
 */
(function(){
  var width = screen.width;
  var oldViewport = document.querySelector('meta[name="viewport"]');
  var viewport = document.createElement('meta');
  viewport.setAttribute('name', 'viewport');
  viewport.setAttribute('content', 'width=' + (width <= 640 ? '640' : 'device-width'));
  document.head.replaceChild(viewport, oldViewport);
})();


// some another solution
if (window.devicePixelRatio !== 1) { // Костыль для определения иных устройств, с коэффициентом отличным от 1
  var dpt = window.devicePixelRatio;
  var widthM = window.screen.width * dpt;
  var widthH = window.screen.height * dpt;
  document.write('<meta name="viewport" content="width=' + widthM+ ', height=' + widthH + '">');
}

$(function() {
  if (navigator.userAgent.match(/iPhone/i) || navigator.userAgent.match(/iPad/i)) {
    var viewportmeta = document.querySelector('meta[name="viewport"]');
    if (viewportmeta) {
      viewportmeta.content = 'width=device-width, minimum-scale=1.0, maximum-scale=1.0, initial-scale=1.0';
      document.body.addEventListener('gesturestart', function () {
        viewportmeta.content = 'width=device-width, minimum-scale=0.25, maximum-scale=1.6';
      }, false);
    }
  }
});
	/*
	* Paste into the end <head>
	*/
	(function(){
	var width = screen.width;
	var oldViewport = document.querySelector('meta[name="viewport"]');
	var viewport = document.createElement('meta');
	viewport.setAttribute('name', 'viewport');
	viewport.setAttribute('content', 'width=' + (width <= 640 ? '640' : 'device-width'));
	document.head.replaceChild(viewport, oldViewport);
	})();


	// some another solution
	if (window.devicePixelRatio !== 1) { // Костыль для определения иных устройств, с коэффициентом отличным от 1
	var dpt = window.devicePixelRatio;
	var widthM = window.screen.width * dpt;
	var widthH = window.screen.height * dpt;
	document.write('<meta name="viewport" content="width=' + widthM+ ', height=' + widthH + '">');
	}

	$(function() {
	if (navigator.userAgent.match(/iPhone/i) \|\| navigator.userAgent.match(/iPad/i)) {
	var viewportmeta = document.querySelector('meta[name="viewport"]');
	if (viewportmeta) {
	viewportmeta.content = 'width=device-width, minimum-scale=1.0, maximum-scale=1.0, initial-scale=1.0';
	document.body.addEventListener('gesturestart', function () {
	viewportmeta.content = 'width=device-width, minimum-scale=0.25, maximum-scale=1.6';
	}, false);
	}
	}
	});