<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript" src="js/jquery.js" ></script>
<script >
$(function(){
$('#btn').prop("disabled",true);
var num =5;
var st = setInterval(function(){
num--;
$('#btn').val("請仔細閱讀協議("+num+")");
if(num==0){
clearInterval(st);
$('#btn').val("同意");
$('#btn').prop("disabled",false);
}
},1000);
});
</script>
</head>
<body>
<input type="button" id="btn" value="請仔細閱讀協議(5)" />
</body>
</html>
