function mostrar(id) {
		if (document.getElementById(id)) {
			var desc = document.getElementById(id).style;
			if (desc.display == "block")
				desc.display = "none";
			else
				desc.display = "block";
			return false;
		} else
			return true;
	}
	
	function overSec(clase,id) {
		mostrar("desc_" + id);
		switch (clase) {
			case "laminadas": 	document.img_lam.src = "images/" + id + ".jpg"; break;
		}
	}
	
	function outSec(clase,id) {
		mostrar("desc_" + id);
		switch (clase) {
			case "laminadas": 	document.img_lam.src = "images/" + "laminadas.jpg"; break;
		}
	}