arrow keys

[coolChews]

is there a way to navigate through forms using the arrow keys to simulate the "tab" key? i've been using the following codes but i encountered a problem when the code met a dropdown list box. could anyone help..

function move(){
var k = event.keyCode;
var l = event.srcElement.form.elements.length;
var tIndex = event.srcElement.tabIndex;

if(k == 38 )
{
tIndex = ( tIndex == 0 ) ? 1 : tIndex
if (tIndex > 1)
{
focus(l, tIndex-1);
}
}
else if(k == 40 )
{
tIndex = ( tIndex >= (l - 1) ) ? (l-2) : tIndex;
focus(l, tIndex+1);
}
}

function focus(l, tIndex)
{
for (i = 0; i < l; i++)
{
if (document.forms[0].elements[i].tabIndex == tIndex)
{
document.forms[0].elements[i].focus();
break;
}
}
}