为什么同样是praseInt().一个出来结果，一个出不来呢
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>History对象</title>
</head>
<script type="text/javascript">
document.write(parseInt("40 g") + "<br/>");
document.write(praseInt("34 d")+ "<br/>");
</script>
<body>
</body>
</html>
