Definition of JS two-dimensional array_javascript skills

1. The way to declare a two-dimensional array is as follows:
var images=new Array();
//Declare one dimension first
for(var i=0;i<10;i ){
//One-dimensional length is 10 images[i]=new Array();
//Declaring two-dimensional for(var j=0;j<20;j ){
// The two-dimensional length is 20 images[i][j]=1; } }

2. The way to use the secondary array should be like this: alert(images[0][0]);