function update()
    {
    with (document.forms[0])
        {
        drinks=numDrinks.selectedIndex+1;
        ozbase=base.options[base.selectedIndex].value;
        drinkTime=time.options[time.selectedIndex].value;
        weightList=weight.options[weight.selectedIndex].value;
        }
    oz=(ozbase*drinks-.5*drinkTime);
    if (oz<.75) i=0;
    else if (oz<1.25) i=2;
    else if (oz<1.75) i=4;
    else if (oz<2.25) i=6;
    else if (oz<2.75) i=8;
    else if (oz<3.25) i=10;
    else if (oz<3.75) i=12;
    else if (oz<4.25) i=14;
    else if (oz<4.75) i=16;
    else i=18;
    j=i+2;
    bac=weightList.substring(i,j);
    document.forms[0].result.value="." +bac;
    if(bac<5) 
	{
		imp="Possible impairment. Drink some more lightweight.";
	}
    else if (bac<8) 
	{
		imp="Some impairment.  You probably don't want to drive, so... keep drinking!";
	}
    else if (bac<10) 
	{
		imp="Definite impairment, illegal in ALL states.  No driving for you.";
	}
    else if (bac<25) 
	{
		imp="Obvious Impairment, illegal to drive in ALL states.";
	}
    else 
	{
		imp="Would you like some blood with your alcohol?  You're definitely not driving tonight.";
	}
    document.forms[0].impair.value=imp;
    }