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" name="q17length" size="3" maxlength="3" value="500"> characters left</i><br/><textarea onKeyDown="textCounter(document.frmSurvey.q17,document.frmSurvey.q17length,500);"
						onKeyUp="textCounter(document.frmSurvey.q17,document.frmSurvey.q17length,500)" class="scanwid" name="q17" id="q17" rows="5" cols=""></textarea></td>
							</tr>

JavaScript

function textCounter(field,cntfield,maxlimit) {
		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;
		}