pc 가로 드래그 기능

      const slider = document.querySelector('.tag_ul');
      let isDown = false;
      let startX;
      let scrollLeft;

      slider.addEventListener('mousedown', (e) => {
        isDown = true;
        startX = e.pageX - slider.offsetLeft;
        scrollLeft = slider.scrollLeft;
      });
      slider.addEventListener('mouseleave', () => {
        isDown = false;
      });
      slider.addEventListener('mouseup', () => {
        isDown = false;
      });
      slider.addEventListener('mousemove', (e) => {
        if(!isDown) return;
        e.preventDefault();
        const x = e.pageX - slider.offsetLeft;
        const walk = (x - startX) * 2; //scroll-fast
        slider.scrollLeft = scrollLeft - walk;
      });

 

출처: https://codepen.io/thenutz/pen/VwYeYEE