function setMaxLength() {
	var x = document.getElementsByTagName('textarea');
	var counter = document.createElement('div');
	counter.className = 'counter';
	for (var i=0;i<x.length;i++) {
		if (x[i].getAttribute('maxlength')) {
			var counterClone = counter.cloneNode(true);
			counterClone.relatedElement = x[i];
			counterClone.innerHTML = '<span>0</span>/'+x[i].getAttribute('maxlength');
			x[i].parentNode.insertBefore(counterClone,x[i].nextSibling);
			x[i].relatedElement = counterClone.getElementsByTagName('span')[0];

			x[i].onkeyup = x[i].onchange = checkMaxLength;
			x[i].onkeyup();
		}
	}
}

function checkMaxLength() {
	var maxLength = this.getAttribute('maxlength');
	var currentLength = this.value.length;
	if (currentLength > maxLength) {
		this.relatedElement.className = 'toomuch';
		this.relatedElement.firstChild.nodeValue = maxLength;
		this.value = this.value.substring(0,maxLength);
		//alert("Debe ingresar hasta un maximo de "+maxLength+" caracteres");
	}else{
		this.relatedElement.className = '';
		this.relatedElement.firstChild.nodeValue = currentLength;
		// not innerHTML
	}
}