检测一个变量是否为字符串

<!DOCTYPE html>
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<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script type="text/javascript">
    var str='123asd';
    //法1
    console.log(typeof str==='string'); //true
    //法2
    console.log(str.constructor===String); //true

    console.log(str instanceof String); //false
    //法3
    console.log(Object.prototype.toString.call(str)==='[object String]')


</script>

</body>
</html>
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原文地址：https://www.cnblogs.com/sakura-sakura/p/6826459.html