jquery window.width if/doesnt working

Question

有人可以告訴爲什麼這個腳本不工作？該腳本嘗試根據窗口寬度滾動後添加類。我不知道我在哪裏犯錯。任何人？

$(document).ready(function() { 
    var nav = $('nav'); 
    var ul = $('ul.navigation li'); 
    var width = $(window).width(); 

    function nav() { 
     if (width < 700) { 
      navbar1(); 
     } else { 
      navbar2(); 
     } 
    }; 

    function navbar1() { 
     $(window).scroll(function() { 
      var scroll = $(window).scrollTop(); 

      if (scroll > 10) { 
       nav.addClass('scroll'); 
       ul.addClass('scroll'); 
      } else { 
       nav.removeClass('scroll'); 
       ul.removeClass('scroll'); 
      } 
     }); 
    } 

    function navbar2() { 
     $(window).scroll(function() { 
      var scroll = $(window).scrollTop(); 
      if (scroll > 10) { 
       nav.addClass('scroll'); 
      } else { 
       nav.removeClass('scroll'); 
      } 
     }); 
    } 
}); 

Answer 1

那就是：https://jsfiddle.net/ggozdyra/hLazq8c7/

$(document).ready(function() { 
    var nav = $('nav'); 
    var ul = $('ul.navigation li'); 
    var width = $(window).width(); 

function kupa(){ 

    if (width < 700) { 
     navbar1(); 
    } else { 
     navbar2(); 
    }; 
}; 

function navbar1() { 
    $(window).scroll(function() { 
     var scroll = $(window).scrollTop(); 

     if (scroll > 10) { 
      nav.addClass('scroll'); 
      ul.addClass('scroll'); 
     } else { 
      nav.removeClass('scroll'); 
      ul.removeClass('scroll'); 
     } 
    }); 
} 

function navbar2() { 
    $(window).scroll(function() { 
     var scroll = $(window).scrollTop(); 
     if (scroll > 10) { 
      nav.addClass('scroll'); 
     } else { 
      nav.removeClass('scroll'); 
     } 
    }); 
    } 

});