Mentions AJAX Drop-down
Mentions AJAX Dropdown for WordPress is a lightweight plugin that enables you to easily find and mention users while writing in bbPress, BuddyPress, and even in the admin dashboard post editor.
Although the plugin states bbPress and BuddyPress in the title, none of these plugins are required in order for Mentions AJAX Dropdown to work, as you can implement it to work with other fields whether in the admin or front-end, as it is quite easier to integrate it. When it comes to technical requirements, this plugin requires at least PHP 5.3, and can work with any latest WordPress install.
Mentions AJAX dropdown is lightweight and users query is cached, so you wouldn’t worry about performance and it loads faster! It is also easy to integrate to work with other fields, easy to extend and fully customizable.
Integrating Mentions AJAX Dropdown is simple and easy, to implement it to work with extra fields or other plugins.
USING PLUGIN SETTINGS:
You can navigate to the plugin settings interface, going to Dashboard > Options > Mentions Dropdown, and check “Show advanced settings” then, in “Targeted Fields” setting, add the DOM selector for the fields you want to add mentions dropdown feature to.
An example, I have a text box with id attribute set to “my-text” added to the bottom of each post, and I want to enable mentions dropdown on it, I will simply go to settings and add #my-text after a comma onto the previously mention setting.