请问下，为什么var int=setInterval(clock,1000)不可以放到function clock(){}里面
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>定时器</title>
<script type="text/javascript">
function clock(){
var time=new Date();
document.getElementById("clock").value = time;
}
var int=setInterval(clock,1000)
</script>
</head>
<body>
<form>
<input type="text" id="clock" size="50" />
</form>
</body>
</html>
上面这段代码为什么不能这样？
<script type="text/javascript">
function clock(){
var time=new Date();
document.getElementById("clock").value = time;
var int=setInterval(clock,1000);
}
</script>
谢谢大神指导
