main.html
<html>
<head>
<script type="text/javascript" src="filealert.js"></script>
<script type="text/javascript">
fn = function () {
var fn = fnAlert; //引用fnAlert函数
fn(123);
};
</script>
</head>
<body onclick="fn()">
</body>
</html>
filealert.js
function fnAlert(str) {
alert(str);
}
