JSFiddle - React, Tailwind, and code Playground

HTML

<div id="mk-nav-search-wrapper" class="mk-box-to-trigger">
             <form method="get" id="mk-header-navside-searchform" action="' . home_url() . '">
                    <input type="text" value="" name="s" id="mk-ajax-search-input" />
                    <i class="mk-moon-search-3 nav-side-search-icon"><input value="" type="submit" /></i>
             </form>
</div>

JavaScript

$('#mk-ajax-search-input').on('keyup', function() {
    this.value = this.value.replace(/\W/, '');
});