$(function(){

getos = getWindow();

$("#rock").click(function(){
$(getos).animate({scrollTop:0},"slow" );
});

});

var getWindow = function() {
	var elem;
	if(!jQuery.support.checkOn) {
		elem = 'html,body'; //chrome,safari
	} else if(jQuery.support.checkOn && jQuery.support.noCloneEvent && window.globalStorage) {
		elem = 'html,body'; //FireFox
	} else if (!jQuery.support.opacity){
		//IE6,7,8
		elem = 'html';
		if(!jQuery.support.style && typeof document.documentElement.style.maxHeight == "undefined") {
			elem = 'body'; //IE6
		}
	} else {
		elem = 'html'; //Oprea IE9 
	}
	return jQuery(elem);
}