JSFiddle - React, Tailwind, and code Playground

HTML

<div class="inputQty">
        <span class="up">up</span>         
     <input type="text" maxlength="6" name="oa_quantity" class="input-quantity"  value="1"/> 
         <span class="down">down</span>
</div>

CSS

span{ cursor: pointer;}

JavaScript

$('.up').on('click',function(){
var UpNum = parseInt($('.input-quantity').val());
if(up.clicked){

}


$('.input-quantity').val(parseInt($('.input-quantity').val())+1);
});

$('.down').on('click',function(){
    $('.input-quantity').val(parseInt($('.input-quantity').val())-1);
});