iPad, iPod and iPhone initial scale
(function(doc) {
var viewport = document.getElementById('viewport');
if ( navigator.userAgent.match(/iPhone/i) || navigator.userAgent.match(/iPod/i)) {
doc.getElementById("viewport").setAttribute("content", "width=1024,initial-scale=0.469");
} else if ( navigator.userAgent.match(/iPad/i) ) {
doc.getElementById("viewport").setAttribute("content", "initial-scale=1.0");
}
}(document));