panel_hider.js

var opened = true // toggle
  , map_width
  , side_panel_width
  , OPEN_SIDEBAR_WIDTH = 30
  , MAX_MAP_WIDTH = 100

var self = this;

$("#toggle").on('click', function() {
     
    var close_it = function () {
          self.map_width = MAX_MAP_WIDTH; // should be a constant
          self.side_panel_width = MAX_MAP_WIDTH - MAX_MAP_WIDTH;
          return false;
      }
      , open_it = function () {
          self.map_width = MAX_MAP_WIDTH - OPEN_SIDEBAR_WIDTH;
          self.side_panel_width = OPEN_SIDEBAR_WIDTH;
          return false;
      }
    
    if (!opened) open_it()
    else close_it()
    
    $("#map").animate({'width': self.map_width.toString() + '%'}, 300);
    $("#side_panel").animate({'width': self.side_panel_width.toString() + '%'}, 300);
   
    opened = !opened;
});