【テスト】
<script type="text/javascript">$(function(){$('body').css('background-color','red');});</script>
<hr color="red">
<input type="button" value="Check" onclick="myfunc()">
<script>var myfunc = function () {alert("Hello world!");}</script>
</div>
<div style="background-color:#ff0000; width:200px; height:100px;" >
<hr color="red">
<input type="button" value="Check" onclick="myfunc()">
<script>var myfunc = function () {alert("Hello world!");}</script>
</div>