Javascript hack which is working on iOS 7. This is based on @dlo 's answer but mouseover and mouseout events are replaced by touchstart and touchend events. Basicly this script add a half second timeout before the zoom would enabled again to prevent zooming.
$("input[type=text], textarea").on({ 'touchstart' : function() {
zoomDisable();
}});
$("input[type=text], textarea").on({ 'touchend' : function() {
setTimeout(zoomEnable, 500);
}});
function zoomDisable(){
$('head meta[name=viewport]').remove();
$('head').prepend('<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=0" />');
}
function zoomEnable(){
$('head meta[name=viewport]').remove();
$('head').prepend('<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=1" />');
}