JSFiddle - React, Tailwind, and code Playground

HTML

<tr id="rq17">
								<td class='qnum'>17.</td>
								<td class='qtext'>Questions? <i>Maximum of 500 characters - <input style="color:red;font-size:12pt;font-style:italic;" readonly type="text" id='q17length' name="q17length" size="3" maxlength="3" value="500"> characters left</i><br/><textarea onKeyDown="textCounter(this,500);"
						onKeyUp="textCounter(this,'q17length' ,500)" class="scanwid" name="q17" id="q17" rows="5" cols=""></textarea></td>
							</tr>

JavaScript

function textCounter(field,cnt, maxlimit) {         
	var cntfield = document.getElementById(cnt)	
     if (field.value.length > maxlimit) // if too long...trim it!
		field.value = field.value.substring(0, maxlimit);
		// otherwise, update 'characters left' counter
		else
		cntfield.value = maxlimit - field.value.length;
}