JSFiddle - React, Tailwind, and code Playground

HTML

<textarea class="my_textarea" rows="1" type="text" placeholder="Reply to Joe..."></textarea>
<textarea class="my_textarea" rows="1" type="text" placeholder="Reply to Jane..."></textarea>

JavaScript

var placeholderValues = [];

function changePlaceholder() {
    if( $(window).width() < 920 ){
        $('.my_textarea').attr('placeholder','Reply test...');
    } else {
      $('.my_textarea').each(function(i){
           $(this).attr('placeholder', placeholderValues[i]);
       });
    }   
}

// initiate first
changePlaceholder();

//get values
$('.my_textarea').each(function(){
   placeholderValues.push($(this).attr('placeholder'));
});

// resize
$(window).resize( changePlaceholder );