Prevent extra space from line break when adding text at then end of a too small textarea

placeholder.js

function placeholder2text(textElementId, text)
{
	var textElement	= document.getElementById(textElementId);
	
	if(textElement.createTextRange && textElement.caretPos)
	{
		var caretPos = textElement.caretPos;
    	caretPos.text = caretPos.text.charAt(caretPos.text.length - 1) == ' ' ? text + ' ' : text;
    	textElement.focus();
  	}
	else
	{
  		textElement.value  += text;
  		textElement.focus();
	 }
}

textarea.html

<textarea name="description" id="description" rows="18" cols="55" wrap="physical">

This script adds a text e.g. in the format {CATEGORY->placeholder} at the end of an textarea. Unfortunately if the textarea is too small and the word is too long it adds an extra space where the line breaks. How to prevent this?