JS 变量和函数的提升

https://www.cnblogs.com/zhangxiaos/p/6215420.html

<script>

    var obj = new Object();
    console.log(obj.aaa);
    obj.aaa = function () {
        alert(1);
    }
    console.log(obj.aaa);

    console.log(document.onclick);

    document.onclick = fn;

    function fn(){
        console.log(1);
    }

    console.log(document["onclick"]);
    
    

</script>