Checkbox total change colour if greater than & check another checkbox

Hi All,

I have a textbox successfully calculating the total of checkboxes checked: 

var total = 0;
for (var i=1; i<=22; i++) {
if (this.getField("OC"+i).value!="Off") total++;
}
event.value = total;

I would like the text to turn red if the total value is greater than 11 and also check another checkbox if the value is greater than 10.

Can anybody help?