application.js

var application = {
  page_loaded : false,
  
  page_init : function() {
    var i;
    application.page_loaded = true;
    
    // Load scripts that have not already been loaded.
    var script;
    for (i=0; script = application.scripts_to_load[i]; i++) {
      application.load_script(script[0], script[1]);
    }
    application.scripts_to_load = [];
  },
  
  
  scripts_to_load : [],
  
  // Dynamically loads a script
  // Waits until the DOM is read to append the script to body
  load_script : function(url, args) {
    if (!this.page_loaded) {
      this.scripts_to_load.push([url, args]);
    } else {
      var script = document.createElement('script');
      script.type = 'text/javascript';
      var arg_array = [];
      for ( v in args) {
        arg_array.push(v.html_entities() + '=' + args[v].html_entities());
      }
      var arg_string = arg_array.join('&');
      script.src = url + '?' + arg_string;
      document.body.appendChild(script);
    }  
  }
};

// You can load the init with jQuery like so:
$(document).ready(application.page_init);

// Call the load script like this:
application.load_script('http://maps.google.com/maps/api/js', {
  v : '3.2',
  sensor : 'false',
  key : 'google_key',
  callback : 'google_init'
});