var preloadFlag = false;

function change( imgName, imgLocation ){document[imgName].src = imgLocation ;}

function newImage( imgSrc ){var imgName = new Image();imgName.src = imgSrc;return imgName;}

function toggle(o){
	var e = document.getElementById(o);
	e.style.display = (e.style.display == 'none') ? 'block' : 'none';
}

function loadImages()
{
 if(document.images)
 {ourprom_o = newImage("images/m_ourprom_on.jpg");
	const_o = newImage("images/m_const_on.jpg");
	comm_o = newImage("images/m_comm_on.jpg");
	prot_o = newImage("images/m_prot_on.jpg");
	 preloadFlag = true;
 }
}

    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;
    }