JSFiddle - React, Tailwind, and code Playground

HTML

<div id="first">first</div>
<div id="second">second</div>
<div id="third">third</div>

<input type="button" value="click!" onclick="abc()">
<input type="button" value="other click!" onclick="xyz()">

JavaScript

var arr = new Array();
arr[0] = 0;
arr[1] = 1;

function abc(){
    alert("before "+arr.length);
    //arr.length =0;// expected to empty the array
    arr = [];
    alert("after length=0 "+arr.length);
    $("div").each(function(){
        arr = arr + $(this).html();
        alert("inside inner function "+arr.length);
    });
    alert("final "+arr.length);
}

function xyz(){
    var a = [];
    alert(typeof(a+$("#first").html()));
}