How to implement a picture sliding component with scroll bar in jquery

jQuery is a widely used JavaScript library that simplifies the complexities of JavaScript programming. Scroll bars are common elements on websites. You can easily implement a picture sliding component with scroll bars by using jQuery. In this article, we will introduce how to use jQuery to implement this function.

First, we need to introduce the jQuery library. You can download the latest version of the library file from jQuery's official website, or use a CDN (Content Delivery Network) link. Here we use the CDN link to load the jQuery library:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>

Next, we need some styles to define the style of the scroll bar. Here we use CSS to define the style for the scroll bar. It should be noted that some class names that will be mentioned later in this article are used here. If you want to change these class names, you need to change the corresponding code at the same time.

.scroll-box {
  overflow: hidden; /* 隐藏滚动条 */
  position: relative;
}

.scroll-box .scroll-content {
  position: absolute;
  left: 0;
  top: 0;
  white-space: nowrap;
}

.scroll-box .scroll-bar {
  background-color: #ccc;
  border-radius: 10px;
  cursor: pointer;
  height: 100%;
  position: absolute;
  right: 0;
  top: 0;
  width: 8px;
  z-index: 1;
}

.scroll-box .scroll-bar .thumb {
  background-color: #999;
  border-radius: 5px;
  height: 50px;
  left: -10px;
  position: absolute;
  top: 0;
  width: 28px;
}

Next, we need the HTML structure to define the image area, scroll bar area and slider.

<div class="scroll-box">
  <div class="scroll-content">
    <img src="image1.jpg" alt="Image 1">
    <img src="image2.jpg" alt="Image 2">
    <img src="image3.jpg" alt="Image 3">
    <img src="image4.jpg" alt="Image 4">
    <img src="image5.jpg" alt="Image 5">
    <img src="image6.jpg" alt="Image 6">
    <img src="image7.jpg" alt="Image 7">
    <img src="image8.jpg" alt="Image 8">
  </div>
  <div class="scroll-bar">
    <div class="thumb"></div>
  </div>
</div>

In the above code, we use the "scroll-box" class name to define the container containing pictures and scroll bars, use the "scroll-content" class name to define the picture area, and use "scroll- bar" class name to define the scroll bar area, and use the "thumb" class name to define the slider.

Next, we need some JavaScript code to implement the scrolling of the image. Before doing this, we need to define a width for each image in order to calculate the distance required to scroll. Here we set the width of the image to 300 pixels:

.scroll-box .scroll-content img {
  display: inline-block;
  width: 300px;
}

Now, we can start writing JavaScript code. First, we need to calculate the height of the slider. The height will be calculated based on the ratio of the image container height to the content area height. We set the slider's height to 80 pixels (you can change it if needed):

var content_height = $('.scroll-content').height();
var container_height = $('.scroll-box').height();
var thumb_height = container_height / content_height * container_height;
$('.thumb').css('height', thumb_height);

Next, we need to bind the slider's drag event in response to the user's scrolling. As the user drags the slider, we move the image content area up or down and update the slider's position.

var is_drag = false;
var start_y = 0;
var start_top = 0;
$('.thumb').mousedown(function(e) {
  is_drag = true;
  start_y = e.pageY;
  start_top = parseInt($(this).css('top'));
});

$(document).mousemove(function(e) {
  if (is_drag) {
    var diff = e.pageY - start_y;
    var thumb_top = start_top + diff;
    var max_top = container_height - thumb_height;
    if (thumb_top < 0) {
      thumb_top = 0;
    }
    if (thumb_top > max_top) {
      thumb_top = max_top;
    }
    var scroll_top = thumb_top / max_top * (content_height - container_height);
    $('.scroll-content').css('top', -scroll_top);
    $('.thumb').css('top', thumb_top);
  }
});

$(document).mouseup(function() {
  is_drag = false;
});

In the above code, we bind the mouse press, mouse move and mouse lift events. When the mouse is pressed, we set the "is_drag" variable to true, indicating that the user is dragging the slider, and save the current mouse position and slider position. When the mouse moves, we calculate the new position of the slider and the new position of the image content area based on the mouse movement distance, and then update the positions of the slider and image content area. Finally, when the mouse is lifted, we set the "is_drag" variable to false, indicating that the user has stopped dragging.

Now, we have implemented a jQuery image scroll bar component. This component allows users to easily scroll through images using a slider, greatly improving user experience and usability.

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