function checkNumber(input, min, max, msg)

{

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



    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;

        }

    }

    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)

{

    if ((form.payments.value == null || form.payments.value.length == 0) ||

        (form.interest.value == null || form.interest.value.length == 0) ||

        (form.principal.value == null || form.principal.value.length == 0)) {

        return;

    }



    if (!checkNumber(form.payments, 1, 480, "# of payments") ||

        !checkNumber(form.interest, .001, 99, "Interest") ||

        !checkNumber(form.principal, 100, 10000000, "Principal")) {

        form.payment.value = "Invalid";

        return;

    }



    var i = form.interest.value;

    if (i > 1.0) {

        i = i / 100.0;

        form.interest.value = i;

    }

    i /= 12;



    var pow = 1;

    for (var j = 0; j < form.payments.value; j++)

        pow = pow * (1 + i);

    form.payment.value = (form.principal.value * pow * i) / (pow - 1);
		
		form.totalint.value = (form.payment.value * form.payments.value)
    - form.principal.value

}



function clearForm(form)

{

    form.payments.value = "";

    form.interest.value = "";

    form.principal.value = "";

}

function validate_contact(form){
	if (form.fname.value==''){
 	 alert('Please enter first name!');
	 return false;
 	}
	if (form.phone.value==''){
 	 alert('Please enter a telephone number!');
	 return false;
 	}
	if (form.email.value==''){
 	 alert('Please enter a valid email address!');
	 return false;
 	}
}

function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}