index.html:
<!DOCTYPE html>
<html>
<head></head>
<body>
<iframe src="iframe1.html" width="116" height="86" align="left"></iframe>
<iframe src="iframe2.html" width="116" height="86" align="left"></iframe>
</body>
</html>
iframe1.html:
<!DOCTYPE html>
<html>
<head>
<style type="text/css">
img {
width: 90px;
height: 70px;
}
</style>
<script type="text/javascript">
window.onload = function(){
document.getElementsByTagName('img')[0].onclick = function(){
parent.frames[1].document.getElementsByTagName('img')[0].src = 'https://developer.mozilla.org/skins/mdn/Transitional/img/mdn-logo-compact.png';
};
};
</script>
</head>
<body>
<img src="http://mrdoob.com/files/blog/header.png" alt="" />
</body>
</html>
iframe2.html:
<!DOCTYPE html>
<html>
<head>
<style type="text/css">
img {
width: 90px;
height: 70px;
}
</style>
</head>
<body>
<img src="http://javascript.ru/forum/images/ca_serenity/misc/logo.gif" alt="" />
</body>
</html>