$(function(){
  var menuwidth  = 180; // 边栏宽度
  var menuspeed  = 300; // 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');
	  $('#hamburgermenu').css('overflow-y','scroll')
    }
	
  });
  
  $('.overlay').on('click', function(e){
    if($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);
    }
  }
});