Navigating with jQuery Keyboard Shortcuts

gistfile1.js

( function ( $ ) {
 
    $( document ).keydown( function( e ) {
        var url = false;
        if ( 37 == e.which ) {  // Left arrow key code
            url = $( '.prev a' ).attr( 'href' ); // set right class
        }
        else if ( 39 == e.which ) {  // Right arrow key code
            url = $( '.next a' ).attr( 'href' ); // set right class
        }
        if ( url ) {
            window.location = url;
        }
    } );
 
} )( jQuery );