nl_tokens: Register a callback to be invoked whenever the browser history changes including using forward and back buttons .
pl_tokens: function ( callback ) { var guid = Ember . guidFor ( this ) , self = this ; Ember . $ ( window ) . on ( 'popstate.ember-location-' + guid , function ( e ) { // Ignore initial page load popstate event in Chrome if ( ! popstateFired ) { popstateFired = true ; if ( self . getURL ( ) === <mask> . _previousURL ) { return ; } } callback ( self . getURL ( ) ) ; } ) ; }