$(function(){
  var menuwidth  = 180; // 边栏宽度
  var menuspeed  = 400; // 边栏滑出耗费时间
  
  var $bdy       = $('body');
  var $container = $('#pgcontainer');
  var $burger    = $('#hamburgermenu');
  var negwidth   = "-"+menuwidth+"px";
  var poswidth   = menuwidth+"px";
  
  $('.menubtn').on('click',function(e){
    if($bdy.hasclass('openmenu')) {
      jsanimatemenu('close');
    } else {
      jsanimatemenu('open');
    }
  });
  
  $('.overlay').on('click', function(e){
    if($bdy.hasclass('openmenu')) {
      jsanimatemenu('close');
    }
  });
  
  function jsanimatemenu(tog) {
    if(tog == 'open') {
      $bdy.addclass('openmenu');
      
      $container.animate({marginright: negwidth, marginleft: poswidth}, menuspeed);
      $burger.animate({width: poswidth}, menuspeed);
      $('.overlay').animate({left: poswidth}, menuspeed);
    }
    
    if(tog == 'close') {
      $bdy.removeclass('openmenu');
      
      $container.animate({marginright: "0", marginleft: "0"}, menuspeed);
      $burger.animate({width: "0"}, menuspeed);
      $('.overlay').animate({left: "0"}, menuspeed);
    }
  }
});