function isNumberKey(evt)
      {
         var charCode = (evt.which) ? evt.which : event.keyCode
         if (charCode > 31 && (charCode < 48 || charCode > 57))
            return false;

         return true;
      }
	  
function update_limit() {		
	if (document.rater.limit.value==2) {
	document.rater.base.value = .005;
	}
	else if (document.rater.limit.value==3) {
	document.rater.base.value = .0075;
	}
	else {
	alert ('Please choose a limit!');
	return false;
	}
}
function update_rate() {
	document.rater.rate.value = (document.rater.base.value * document.rater.agr.value);
}
function update_estimate() {
	if (document.rater.limit.value==2 && document.rater.rate.value > 500) {
		document.rater.estimate.value = document.rater.rate.value;
	}
	else if (document.rater.limit.value==2 && document.rater.rate.value < 501 && document.rater.rate.value > 0) {
		document.rater.estimate.value = 500;
	}
	else if (document.rater.limit.value==3 && document.rater.rate.value > 750) {
		document.rater.estimate.value = document.rater.rate.value;
	}
	else if (document.rater.limit.value==3 && document.rater.rate.value < 751 && document.rater.rate.value > 0) {
		document.rater.estimate.value = 750;
	}
	else {
		document.rater.estimate.value = "";
		alert ('Please make sure that you type in your annual gross receipts and that you have picked a limit!');
		return false;
	}
}