<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title></title>
<script type="text/javascript">
onload = function () {
var i = 5;
var btnObj = document.getElementById(‘btn‘);
setInterval(function () {
i--;
if (i <= 0) {
//当时间小于等于0秒的时候让空间可用
btnObj.disabled = false;
btnObj.value = ‘同意条款‘;
} else {
//当时间还不够的时候继续锁定
btnObj.value = ‘请仔细阅读以上条款‘ + i;
};
}, 1000);
};
</script>
</head>
<body>
<input id="btn" type="button" name="name" value="请仔细阅读以上条款5 " disabled="disabled" style="cursor:pointer" />
</body>
</html>
原文：http://www.cnblogs.com/clcloveHuahua/p/5109450.html