功能是按下按钮，单词如果是good，就变成bad，如果是bad，就变成good
///////////////////////////////////////////////////////////////////////////////
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script type="text/javascript">
function changeword(){
var newword=document.getElementsByClassName('word');
if (newword[0]=="good") {
newword[0]="bad";
}
else{
newword[0]="good";
}
}
</script>
<title>changeword</title>
</head>
<body>
<input type="button" value="changeword" id="abutton" onclick="changeword()">
<p class="word">good</p>
</body>
</html>luofuxiang