Scroll textfield up when keyboard popsup

To complete the answer, if you want to animate the scroll replace:

$htmlOrBody.scrollTop(textareaTop - scrollTopPadding);

by

var timing = 250;
$htmlOrBody.animate({ scrollTop: textareaTop - scrollTopPadding }, timing);

with jQuery, get the textarea's offset().top value then set document scroll position using scrollTop()

var $htmlOrBody = $('html, body'), // scrollTop works on <body> for some browsers, <html> for others
    scrollTopPadding = 8;

$('textarea').focus(function() {
    // get textarea's offset top position
    var textareaTop = $(this).offset().top;
    // scroll to the textarea
    $htmlOrBody.scrollTop(textareaTop - scrollTopPadding);
});

jsfiddle example