var fCaptcha = function() {

	var refreshPicture = function(e) {
		this.parentNode.firstChild.src = this.parentNode.firstChild.src +'?'+ Math.random();
	};

	var initCaptcha = function(root) {

		var button = document.createElement('span');
		button.className = 'refresh-button';
		button.innerHTML = 'Показать другую картинку';
		button.onclick = refreshPicture;
		root.appendChild(button);

	};

	$A($$('.f-captcha')).each(initCaptcha);

};

Event.observe(window, 'load', fCaptcha);