javascript multidimensional Array and associative array -

i new of javascript, have been told someone, said "speak strictly, javascript doesn't have multidimensional array , associative array ". in book, saw following

var my_cars=array(); my_cars["cool"]="mustang";  $a=array(array(0,1),2); 

so opinion form wrong? right?

javascript has arrays of whom elements can other arrays.

however, javascript has objects properties, not associative arrays.

buy better book.

1. [] better array(). also, why not instantiate array object explicitly rely on array returning new object?
2. the example setting property cool on array.
3. why $a sigil? why no new operator again?