array length problem? please help

[tsongwei]

I have a 2 dimensioinal array like this
a[X][Y]
a[0][0]=1;
a[0][1]=1;
a[0][2]=1;
a[0][3]=1;
a[0][4]=1;
a[0][5]=1;
a[1][0]=1;
a[1][1]=1;
a[1][2]=1;
a[1][3]=1;
a[1][4]=1;

now, how do I know the lengh of a[0][Y]? or a[1][Y]?
I tried a[0].lengh, but it's not working.
Does anyone know how to I get it's length?

Thanks!!

[pyro]

Are you defining your seconds arrays? Here is a quick sample of a multidimensional array:

<script language="JavaScript" type="text/JavaScript">

//set up arrays
a = new Array();
a[0] = new Array();
a[1] = new Array();
//set up values
a[0][0]=1;
a[0][1]=1;
a[0][2]=1;
a[0][3]=1;
a[0][4]=1;
a[0][5]=1;
a[1][0]=1;
a[1][1]=1;
a[1][2]=1;
a[1][3]=1;
a[1][4]=1;

alert(a[0].length);

</script>