typeof 是JavaScript的运算符
——返回一个用来表示表达式的数据类型的字符串
typeof[(] expression [)] //typeof语法中的圆括号是可选项
typeof 运算符@import url(../html-vss/msdnie4a.css);
typeof
运算符把类型信息当作字符串返回。typeof
返回值有六种可能： "number," "string,"
"boolean," "object," "function," 和 "undefined."
实例<html>
<head>
<title>typeof测试用例页面</title>
<mce:script type="text/javascript"><!--
t = function(i) {
alert(typeof 123);//number
alert(typeof("123"));//String
}
// --></mce:script>
<mce:style type="text/css"><!--
div {
opacity: 0.5;
}
--></mce:style><style type="text/css" mce_bogus="1"> div {
opacity: 0.5;
}
</style>
</head>
<body>
<div onclick="t(1)">测试typeof</div>
</body>
</html>
