<body>
<p>判断是否是数组</p>
<p id="demo"></p>
</body>
</html>
<script>
var arr = [12, 23, 34, 56];
document.getElementById("demo").innerHTML = isArray(arr);
function isArray(arr) {
let fn = arr.constructor;
let str = fn.toString();
let ar = str.indexOf("Array") != -1;
// return arr.constructor.toString().indexOf("Array")!=-1; //true
return fn + ' +++ ' + str + ' ---- ' + typeof str + ' *** ' + ar
}
</script>
运行结果如下：
image.png
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