第1个回答 推荐于2016-02-14
<!DOCTYPE HTML>
<html>
<head>
<meta charset=UTF-8 />
<title>Nothing</title>
<style type="text/css">
#txt {
font-size: 12px;
}
</style>
<script type="text/javascript">
onload = function ()
{
txt.onkeyup = function ()
{
this.style.fontSize = '25px';
}
}
</script>
</head>
<body>
<input type="text" id="txt" />
</body>
</html>本回答被提问者和网友采纳