Designing with JavaScript CD Code

<HTML>
<HEAD><TITLE>Validate This!</TITLE>
<SCRIPT LANGUAGE = "JavaScript">

// Is it A posative integer?
function isInt(elm) {
var elmstr = elm.value + ""; 
    if (elmstr == "") return false;
    for (var i = 0; i < elmstr.length; i++) {
        if (elmstr.charAt(i) < "0" ||
            elmstr.charAt(i) > "9") {
        return false;
        }
    }
return true;
}

// Is it a phone number?
function isPhone(elm) {
var elmstr = elm.value + "";
    if (elmstr.length != 12) return false;
    for (var i = 0; i < elmstr.length; i++) {
        if ((i < 3 && i > -1) ||
            (i > 3 && i < 7) || 
            (i > 7 && i < 12)) {
            if (elmstr.charAt(i) < "0" || 
                elmstr.charAt(i) > "9") return false;
        }
        else if (elmstr.charAt(i) != "-") return false;
    }        
return true;
}


//-->
</SCRIPT>
</HEAD>
<BODY BGCOLOR = "#FFFFFF">
</BODY>
</html>