JSFiddle - React, Tailwind, and code Playground

HTML

<div style="background-color:red; width:100px; height:100px"></div>
<input type="button" value="Show" id="btnShow" />
<input type="button" value="Hide" id="btnHide" />
<select name="ctl00$HeadContent$ddMarkTo" id="HeadContent_ddMarkTo" class="form-control">
	<option selected="selected" value="45">Shahnaz Aziz [Dy. Manager]</option>
	<option value="46">Najam Imran [Assistant Manager]</option>
	<option value="48">Abdul Rehman Baig Mirza [Assistant Manager]</option>
	<option value="250">Raja Azkar Mehmood [IT Officer (Inventory)]</option>
	<option value="252">Tahir Mehmood [Senior Clerk]</option>
	<option value="3130">Muhammad Shahid Khan [Dy. Manager]</option>
	<option value="3142">Iftikhar Shah [Manager]</option>
	<option value="3838">Aftab Hussain [Dy. Manager]</option>
	<option value="3869">Hamid Fayyaz [Naib-Qasid]</option>
	<option value="4357">Yousaf Haroon [Hardware Engineer]</option>
	<option value="4413">Muhammad Adnan Ashraf [IT Officer (Networks)]</option>
	<option value="4415">Lt Col (Retd) Muhammad Aftab [General Manager]</option>
	<option value="4421">Saba Javed [IT Officer]</option>

</select>

JavaScript

$("#btnShow").on("click",function(){$("div").show("slow");});
$("#btnHide").on("click",function(){$("div").hide("slow");});
$("#HeadContent_ddMarkTo").on("change",function(){$("div").hide("slow");});