function checkUserInput(figure, defaultfigure) {
	figure = parseFloat(figure);
		if (isNaN(figure)) figure = defaultfigure;
	figure = Math.sqrt(figure*figure);
	figure = Math.round(figure);
	return figure;
}

function calculateQuote() {
	var squarefeet = document.calculator.elements[0].value;
	var numberfloors = document.calculator.elements[1].value;
	var numberwashrooms = document.calculator.elements[2].value;
	var numberkitchens = document.calculator.elements[3].value;
	var numberlifts = document.calculator.elements[4].value;
	var numbervisits = document.calculator.elements[5][document.calculator.elements[5].selectedIndex].value;

	var basehours = squarefeet/3500;
	var stairhours = (numberfloors-1)*(5/60);
	var washhours = numberwashrooms*(5/60);
	var kitchenhours = numberkitchens*(1/6);
	var lifthours = numberlifts*(5/60);
	var washuphours = 0; 

   if (numberkitchens > 0) washuphours = 0.25;

var hourspervisit = basehours + stairhours + washhours + kitchenhours + lifthours + washuphours;
var hoursperweek = hourspervisit*numbervisits;
var costperweek = hoursperweek*12;

var roundtoten = Math.round(costperweek/10)*10;
var difference = costperweek - roundtoten;
var fivetoadd = 0;

   if (difference > 2.5) fivetoadd = 5;
   if (difference < -2.5) fivetoadd = -5;

var nearestfive = roundtoten + fivetoadd;

var minimum_array = new Array(35, 45, 55, 60);
var minimuminforce = minimum_array[document.calculator.elements[5].selectedIndex];

var finalquote = Math.max(nearestfive, minimuminforce);

   if (isNaN(finalquote)) finalquote = 0;

   if (finalquote == Math.round(finalquote))
   {
   finalquote += '.00';
   }
   else if ((finalquote*10) == Math.round(finalquote*10))
   {
   finalquote += '0';
   }

finalquote = '£' + finalquote;

document.calculator.elements[6].value = finalquote;

}