时间:2021-07-01 10:21:17 帮助过:13人阅读
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script type="text/javascript">
var c=6;
var t;
function timedCount()
{
var time = document.getElementById('txt').value;
if( time>0){
document.getElementById('txt').value=c;
c=c-1;
t=setTimeout("timedCount()",1000);
}
else{
clearTimeout(t);
}
}
</script>
</head>
<body>
<form>
<input type="button" value="开始计时!" onClick="timedCount()">
<input type="text" id="txt" value="6">
</form>
</body>
</html>