Common to the official website of the rocket navigation in the implementation process

1  // When a position to display the navigation side 
2      $ (Document) .scroll ( function () {
 . 3          var scrTop = $ (window) .scrollTop ();
 . 4          var . N_T = $ ( 'body') height ( ) * 0.1 ;
 . 5              IF (scrTop < N_T) {
 . 6                  $ ( '. L_left' ) .hide ()
 . 7              } the else {
 . 8                  $ ( '. L_left' ) the .Show ()
 . 9              }
 10          // rocket portion 
11          $ ( ".L_left .rocket"). the Click ( function () {
 12 is            $("html,body").stop().animate({scrollTop:0},3000);
13         });
14     })