IPv4 Address Validator

validator.js

function ValidateIPaddress(inputText) {
    var ipformat = /^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/;
    if (inputText.value.match(ipformat)) {

        alert("You entered a valid IPv4 address.");
        document.ipform.ipaddr.focus();
        return false;
    } else {
        alert("You entered an invalid IPv4 address.");
        document.ipform.ipaddr.focus();
        return false; }
    }