Q2W3 Fixed Widget for WordPress的作者是Thomas Maier, Max Bond,目前有100,000+个有效安装。已经Tested with 5.4.1版本的wordpress。
Description

Use the fixed widget plugin to create sticky widgets that stay in the visible screen area when the page is scrolled up or down.

Sticky widgets are perceived much better by your visitors than unfixed widgets and therefore have a significantly higher click-through rate. Therefore, this option is especially useful for ads or other items that visitors want to interact with.

The recommended solution for integrating ads in WordPress is the free ad management plugin Advanced Ads.

Manual and demo
COMPATIBILITY

The plugin is not working with all themes! Theme requirements:

jQuery 1.7 is required, jQuery 1.8.3 (or later) is recommended.
No JavaScript errors caused by other plugins and scripts.
wp_head() and wp_footer() functions in header.php and footer.php files.
Widgets must have an ID attribute.

In some themes fixed widgets „jump“ during scrolling, etc. Some CSS changes at your theme will be required in this case.