function checkForZero(field) {
        if (field.value == 0 || field.value.length == 0) {
            alert ("This field can't be 0!");
            field.focus(); }
        else
	    calculatePayment(field.form);
    }

    function cmdCalc_Click(form) {
        if (form.price.value == 0 || form.price.value.length == 0) {
            alert ("The Price field can't be 0!");
            form.price.focus(); }
        else if (form.ir.value == 0 || form.ir.value.length == 0) {
            alert ("The Interest Rate field can't be 0!");
            form.ir.focus(); }
        else if (form.term.value == 0 || form.term.value.length == 0) {
            alert ("The Term field can't be 0!");
            form.term.focus(); }
        else
            calculatePayment(form);
    }

    function calculatePayment(form) {
        princ = form.price.value - form.dp.value;
        intRate = (form.ir.value/100) / 12;
        months = form.term.value * 12;
        form.pmt.value = Math.floor((princ*intRate)/(1-Math.pow(1+intRate,(-1*months)))*100)/100;
	  	form.principle.value = princ;
		form.payments.value = months;
		form.ioPrinciple.value = princ;
		form.ioPayments.value = months;
		form.ioPayment.value = Math.floor((princ*intRate)*100)/100;
    }
    
    function btlCheckForZero(field) {
        if (field.value == 0 || field.value.length == 0) {
            alert ("This field can't be 0!");
            field.focus(); }
        else
	    calculatePayment(field.form);
    }

    function btlCalc_Click(form) {
        if (form.price.value == 0 || form.price.value.length == 0) {
            alert ("The Price field can't be 0!");
            form.price.focus(); }
        else if (form.ir.value == 0 || form.ir.value.length == 0) {
            alert ("The Interest Rate field can't be 0!");
            form.ir.focus(); }
        else
            btlCalculate(form)
    }

    function btlCalculate(form) {
    	var price = form.price.value;
    	var mortgage = form.mortgage.value;
    	var yeild = form.yeild.value;
    	var margin = form.margin.value;
    	var ir = form.ir.value;
    	var irc = form.irc.value;
    	
    	form.repayment.value = Math.floor((mortgage*ir)/12)/100;
    	form.maxAdvance.value = Math.floor((mortgage/price)*10000)/100;
    	
    	var maxPayment = Math.floor((yeild/margin)*10000)/100;
    	form.maxPayment.value = maxPayment;
    	form.maxMortgage.value = Math.floor((((maxPayment/irc)*100)*12)*100)/100;
    	
    }