JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
<textarea cols="55" rows="4" id="message" name="msg"  maxlength="250"   ></textarea>
<p></p>
<input type="button" name="submit" id="submit" value="submit"/>
</div>

JavaScript

$(document).ready(function(){


$("#wrapper").on("click","#submit",function(){
var msg_data = $("#message").val();
      
           var word = /\[(.*?)\]/g;
  var found = msg_data.match(word);
if (found != null) {
alert(found)
}
    
     
});
});