JavaScript ローカル オブジェクト

<script type="text/javascript">var a = [1,2,3];
document.write(a.concat(4,5));</script>

1，2,3,4,5

<script type="text/javascript">var arr = new Array(3)
arr[0] = "George"arr[1] = "John"arr[2] = "Thomas"document.write(arr.join())</script>

George,John,Thomas

<script>var x=[4,5,7,1,6,9,3,10,132,12];
console.log(x.sort());
console.log(x.sort(function(a,b){
    return a-b;
}));
console.log(x.sort(function(a,b){
    return b-a;
})) ;
console.log(x);</script>

[1, 10, 12, 132, 3, 4, 5, 6, 7, 9]
[1, 3, 4, 5, 6, 7, 9, 10, 12, 132]
[132, 12, 10, 9, 7, 6, 5, 4, 3, 1]
[132, 12, 10, 9, 7, 6, 5, 4, 3, 1]

<script type="text/javascript">var arr = new Array(3)
arr[0] = "George"arr[1] = "John"arr[2] = "Thomas"document.write(arr)
document.write("<br />")
document.write(arr.pop())
document.write("<br />")
document.write(arr)</script>

George,John,Thomas
Thomas
George,John

<script type="text/javascript">var arr = new Array(3)
arr[0] = "George"arr[1] = "John"arr[2] = "Thomas"document.write(arr + "<br />")
document.write(arr.push("James") + "<br />")
document.write(arr)</script>

George,John,Thomas
4
George,John,Thomas,James