<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>

<script type="text/javascript">
(function($) {
$(document).ready(function() {
/*
Ads Sidewinder
by Hamachiya2. http://d.hatena.ne.jp/Hamachiya2/20120820/adsense_sidewinder
*/
var main = $('#main'); // メインカラムのID
var side = $('#side'); // サイドバーのID
var wrapper = $('#ad1'); // 広告を包む要素のID

var w = $(window);
var wrapperHeight = wrapper.outerHeight();
var wrapperTop = wrapper.offset().top;
var sideLeft = side.offset().left;

var sideMargin = {
top: side.css('margin-top') ? side.css('margin-top') : 0,
right: side.css('margin-right') ? side.css('margin-right') : 0,
bottom: side.css('margin-bottom') ? side.css('margin-bottom') : 0,
left: side.css('margin-left') ? side.css('margin-left') : 0
};

var winLeft;
var pos;

var scrollAdjust = function() {
sideHeight = side.outerHeight();
mainHeight = main.outerHeight();
mainAbs = main.offset().top + mainHeight;
var winTop = w.scrollTop();
winLeft = w.scrollLeft();
var winHeight = w.height();
var nf = (winTop > wrapperTop) && (mainHeight > sideHeight) ? true : false;
pos = !nf ? 'static' : (winTop + wrapperHeight) > mainAbs ? 'absolute' : 'fixed';
if (pos === 'fixed') {
side.css({
position: pos,
top: '',
bottom: winHeight - wrapperHeight,
left: sideLeft - winLeft,
margin: 0
});

} else if (pos === 'absolute') {
side.css({
position: pos,
top: mainAbs - sideHeight,
bottom: '',
left: sideLeft,
margin: 0
});

} else {
side.css({
position: pos,
marginTop: sideMargin.top,
marginRight: sideMargin.right,
marginBottom: sideMargin.bottom,
marginLeft: sideMargin.left
});
}
};

var resizeAdjust = function() {
side.css({
position:'static',
marginTop: sideMargin.top,
marginRight: sideMargin.right,
marginBottom: sideMargin.bottom,
marginLeft: sideMargin.left
});
sideLeft = side.offset().left;
winLeft = w.scrollLeft();
if (pos === 'fixed') {
side.css({
position: pos,
left: sideLeft - winLeft,
margin: 0
});

} else if (pos === 'absolute') {
side.css({
position: pos,
left: sideLeft,
margin: 0
});
}
};
w.on('load', scrollAdjust);
w.on('scroll', scrollAdjust);
w.on('resize', resizeAdjust);
});
})(jQuery);
</script>