Javascript 条件语句混淆-如果3显示元素

我正在尝试编写一个函数，允许我的用户选择3个元素，一旦选择了3个元素，就会出现“下一步”按钮

我的用户应该被允许取消选择一个答案，并选择另一个，取消选择后，下一步按钮应该淡出，因为现在只有2个元素选择

我正在努力让它有效地工作

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您可以这样简化代码：

    $('.answer').on('click',function(e){
    e.preventDefault();

    var selected = $('.moreAnswers > .selected').length;

    if(selected == 3){ //if selected is 3 we focus on just deselecting
      if($(this).is('.selected')){ //deselcted and remove links
         $(this).removeClass('selected');
         $('.next-question').fadeOut();
          $('.next-question').css('opacity',0);
      } 
    }else{ //toggle and check if this was the 3rd one
        if($(this).is('.selected')){
            $(this).removeClass('selected');
        } else {
            $(this).addClass('selected');
            if(selected == 2){
             $('.next-question').fadeIn();
           $('.next-question').css('opacity',1);
        }
            }
    }
} );

样品

    $('.answer').on('click',function(e){
    e.preventDefault();

    var selected = $('.moreAnswers > .selected').length;

    if(selected == 3){ //if selected is 3 we focus on just deselecting
      if($(this).is('.selected')){ //deselcted and remove links
         $(this).removeClass('selected');
         $('.next-question').fadeOut();
          $('.next-question').css('opacity',0);
      } 
    }else{ //toggle and check if this was the 3rd one
        if($(this).is('.selected')){
            $(this).removeClass('selected');
        } else {
            $(this).addClass('selected');
            if(selected == 2){
             $('.next-question').fadeIn();
           $('.next-question').css('opacity',1);
        }
            }
    }
} );