js constructor 属性返回值

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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runcodex.com)</title>
</head>
<body>
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<p> constructor 属性返回变量或对象的构造函数。</p>
<p id="demo"></p>
<script>
document.getElementById("demo").innerHTML = 
    "john".constructor + "<br>" +
    (3.14).constructor + "<br>" +
    false.constructor + "<br>" +
    [1,2,3,4].constructor + "<br>" +
    {name:'john', age:34}.constructor + "<br>" +
    new Date().constructor + "<br>" +
    function () {}.constructor;
</script>
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</body>
</html>
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