JSFiddle - React, Tailwind, and code Playground

HTML

<p> Hardcoded the id of the SelectMenu (this one works in teh browser althoug not in this fiddle)</p>
<input type="button" name="novariable" id="novariable" value="novariable" onClick="showSelects();">
<select name="sText" id="sText" value="Third">
  <option value="1st">First</option>
  <option value="2nd">Second</option>
  <option value="3rd">Third</option>
</select>
<br><P>
    <p> I want to pass the id of the SelectMenu to the Function</p>
<input type="button" name="variable" id="variable" value="variable" onClick="showSelectsVar('sText2id');">
<select name="sText2id" id="sText2id" value="Third">
  <option value="1st">First</option>
  <option value="2nd">Second</option>
  <option value="3rd">Third</option>
</select>

JavaScript

function showSelects () {
	
		var insertText = document.createTextNode(sText.value);
		var child = document.getElementById('sText');
		child.parentNode.insertBefore(insertText,child);
	}

function showSelectsVar (x) {
		x=document.getElementById(x).value;
		var insertTextVar = document.createTextNode(x);
		var child = document.getElementById(x);
		child.parentNode.insertBefore(insertTextVar,child);
	}