array asociativo multidimensional javascript

1<script type="text/javascript">
2var myObj = { 
3    fred: { apples: 2, oranges: 4, bananas: 7, melons: 0 }, 
4    mary: { apples: 0, oranges: 10, bananas: 0, melons: 0 }, 
5    sarah: { apples: 0, oranges: 0, bananas: 0, melons: 5 } 
6}
7
8document.write( myObject[ 'fred' ][ 'apples' ] );

1var iMax = 20;
2var jMax = 10;
3var f = new Array();
4
5for (i=0;i<iMax;i++) {
6 f[i]=new Array();
7 for (j=0;j<jMax;j++) {
8  f[i][j]=0;
9 }
10}
11