Сергей Щучкин

function isScrolledIntoView(elem)
{
    var docViewTop = $(window).scrollTop();
    var docViewBottom = docViewTop + $(window).height();

    var elemTop = $(elem).offset().top;
    var elemBottom = elemTop + $(elem).height();

    return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}

$str = preg_replace('/\n {4}/',"\n\t", $str);
$str = preg_replace('/\n {4}/',"\n\t", $str);
$str = preg_replace('/\n {4}/',"\n\t", $str);
$str = preg_replace('/\n {4}/',"\n\t", $str);