$(function() {
  var timer = false;
  $(window).on('orientationchange resize', function(){
    if (timer !== false) {
      clearTimeout(timer);
    } else {
      // リサイズ開始
      console.log("viewport: resize start.");
    }
    timer = setTimeout(function() {
      // リサイズ終了
      console.log("viewport: resize end.");
      _setViewport();
      // timerを戻す
      timer = false;
    }, 200);
  });

  _setViewport();

  function _setViewport() {
    var w = screen.width;
    var x = 767;
    if (w <= x) {
      $("meta[name='viewport']").attr('content','width=device-width,initial-scale=1.0');
    } else {
      $("meta[name='viewport']").attr('content','width=1200');
    }
  }
});