JSFiddle - React, Tailwind, and code Playground
HTML
<p>
<select id="page_selection">
<option value="edit1">About All</option>
<option value="edit2">Home Introduction</option>
</select>
<form method="post" action="page_edit_action.php" />
<textarea name="about_all" id="edit1">Test About</textarea>
<textarea name="home_introduction" id="edit2">Test Home</textarea>
</form>
</p>
JavaScript
$(function(){
$('#edit1, #edit2').hide();
$("#page_selection").change(function(){
$("#" + this.value).show().siblings().hide();
}).change();
});