<!--

	//checks that data are valid 

	function checkNumber(input, min, max, msg) {


		msg = msg + " field has invalid data: " + input.value;


		//this makes sure that the number is a number

		var str = input.value;

		for (var i = 0; i < str.length; i++) {

			var ch = str.substring( i, i + 1)

			if ((ch < "0" || "9" < ch) && ch != '.') {

				alert(msg);

				return false;

			}

		}


		//this makes sure that the number lies between the min and max values allowed

		var num = 0 + str

		if (num < min || max < num) {

			alert(msg + " not in range [" + min + ".." + max + "]");

			return false;

		}

		input.value = str;

		return true;

	}


	function computeField(input) {

		if (input.value != null && input.value.length != 0)

		{

			input.value = "" + eval(input.value);

		}

		computeForm(input.form);

	}


	function computeForm(form) {

		var A=form.A.value;

		var T=form.T.value;

		var R=form.R.value;


		//making sure that an entry has been made in each field.

		if ((A == null || A.length == 0) ||

			(R == null || R.length == 0)) 

		{

			//alert('not all fields filled in');

			return;

		}


		// making sure that entries are valid by using check number

		if (!checkNumber(form.A, 1, 9999999, "Amount") ||

			!checkNumber(form.R, .001, 1000, "Interest Rate") ||

			!checkNumber(form.T, 5, 25, "Period"))  

		{

			form.Cm.value = "Invalid";

			return;

		}


		// maths et al to be computed

		R = R / 100;

		var P = ((A*R)/12) * (1/(1-(Math.pow(1/(1+R),T))));

		form.Cm.value = poundsPence( P );

		P = ((A*(R+0.02))/12) * (1 / (1-(Math.pow((1/1.12),T))));

		form.CCm.value = poundsPence( P );

		P = (A*R)/12;

		form.CI.value = poundsPence( P );

		P = (A*(R+0.02))/12;     

		form.CCI.value = poundsPence( P );
		//changed to use a 2% increase on the interest rate that was entered in y the user

	}


	function poundsPence( N ) {

		// don't try this with ie3 because it's rubbish

		if ((navigator.appName.indexOf('Microsoft')>-1)

			&& (navigator.appVersion.indexOf('3.0')>-1) )

		{

			return N;

		}

		S = new String( N );

		var i = S.indexOf('.');

		if (i != -1) {

			S = S.substr( 0, i+3 );

			if (S.length-i < 3)

				S = S + '0';

		}

		return S;

	}


	//clears form

	function clearForm(form) {

		form.A.value = "";

		form.T.value = "";

		form.R.value = "";

	}


//-->