function isaNumber(str) {
	if (str.indexOf (".") != str.lastIndexOf (".")) {
		alert ("Please enter numbers only.");
		return (false);
	};
	for (var i = 0; i < str.length; i++) {
		var ch = str.substring (i, i + 1);
		if (( ch < "0" || ch > "9") && (ch !=".") && (ch != "-")) {
			alert ("Please enter numbers only.");
			return (false);
		}
	};
	return (true);
}

function formatNumber(num) {
	num = "" + num;
	if (num.indexOf (".") == 0) {
		num = "0" + num;
	};
	if (num.indexOf (".") == -1) {
		num = num + ".0";
	};
	num = num + "0";
	return (num.substring (0, num.indexOf (".") + 5));
}

function formatAmNumber(num) {
	num = "" + num;
	if (num.indexOf (".") == 0) {
		num = "0" + num;
	};
	if (num.indexOf (".") == -1) {
		num = num + ".0";
	};
	num = num + "0";
	return (num.substring (0, num.indexOf (".") + 3));
}

function NSclick(e) {
    if (navigator.appName=="Netscape" && parseInt(navigator.appVersion)==4) { 
        if (e.which == 3) {
            return false;
        }
    }
    if (navigator.appName=="Netscape" && parseInt(navigator.appVersion)>=5) { 
            if (e.button == 2 || e.button == 3) {
                  e.preventDefault();
            return false;
          }
    }
}

if (navigator.appName=="Netscape" && parseInt(navigator.appVersion)==4) { 
	document.onmousedown=NSclick;
	document.captureEvents(Event.MOUSEDOWN);
}
if (navigator.appName=="Netscape" && parseInt(navigator.appVersion)>=5) { 
	document.onmouseup=NSclick;
}
if (navigator.appName=="Microsoft Internet Explorer") { 
	document.oncontextmenu = new Function("return false;")
}