function isNumber(x)
{
    var isNum = true;

    for ( inx=0; inx < x.length; inx++ )
    {
        if ( ( x.charAt(inx) < '0' || x.charAt(inx) > '9') && x.charAt(inx) != '-' )
            isNum = false;
    }
    return isNum;
}

function validnum(phone)
{
    validPhoneNum = false;
    if ( isNumber( phone.value ) )
	{
		validPhoneNum = true;
	}
	else
	{
		alert("allowed only NUMBERS and '-' for Phone Number");
		phone.focus();
		phone.select();
	}
    return validPhoneNum;
}