help with this javascript script?

var selectVal = document.forms['theForm'].elements['wheels_tyres_tyres_select'].options;
if (selectVal.value == 'unsure') {
document.getElementById('tbl_help').style.display= '';
}
else {
document.getElementById('tbl_help').style.display= 'none';
}

this works it hides or displays a table if you select unsure from a drop field.

what i want to change is this line
var selectVal = document.forms['theForm'].elements['wheels_tyres_tyres_select'].options;

where it has elements i want to state many elements eg. 'wheels_tyres_tyres_select'
'wheels_select'
'tyres_select'
'hubcaps_select'

so it should read something like if you select unsure from any one of thoes elements then display the table.

cheers aron.