JSFiddle - React, Tailwind, and code Playground

HTML

<div id="name" class="name">dsfdsfsfdsdfdsf</div> 
<div id="address" class="address">sdfsdfdsfdsfdsf </div> 
<div id="address1" class="address1">sdfsdfdsfdsfdsf </div>

<select id="size">
        <option value="7">7</option>
        <option value="10">10</option>
        <option value="20">20</option>
        <option value="30">30</option>
    </select>

JavaScript

$(".name, .address, .address1").on("mousedown", function () {    
    $(this).one("mouseup", function () {        
        if (window.getSelection().toString().length > 0)
            $(this).css('font-size', $('#size').val()+"px");
    });
});