银行账号输入格式实时验证

<script language="javascript" type="text/javascript">
function formatBankNo (BankNo)
{
    if (BankNo.value == "") return;
    var account = new String (BankNo.value);
   
    account = account.substring(0,22); /*帐号的总数, 包括空格在内 */

    if (account.match (".[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{7}") == null)
    {
        /* 对照格式 */
        if (account.match (".[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{7}|" + ".[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{7}|" +
            ".[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{7}|" + ".[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{7}") == null)
        {
            var accountNumeric = accountChar = "", i;
            for (i=0;i<account.length;i++)
            {
                accountChar = account.substr (i,1);
   
                if (!isNaN (accountChar) && (accountChar != " ")) accountNumeric = accountNumeric + accountChar;
            }
   
            account = "";
            for (i=0;i<accountNumeric.length;i++)
            { /* 可将以下空格改为-,效果也不错 */
                if (i == 4) account = account + " "; /* 帐号第四位数后加空格 */
                if (i == 8) account = account + " "; /* 帐号第八位数后加空格 */
    if (i == 12) account = account + " ";/* 帐号第十二位后数后加空格 */
                account = account + accountNumeric.substr (i,1)
            }
        }
    }
    else
    {
        account = " " + account.substring (1,5) + " " + account.substring (6,10) + " " + account.substring (14,18) + "-" + account.substring(18,25);
    }
    if (account != BankNo.value) BankNo.value = account;
}

function checkBankNo (BankNo)
{
    if (BankNo.value == "") return;
    if (BankNo.value.match (".[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{7}") == null)
    {
        if (BankNo.value.match ("[0-9]{19}") != null)
            formatBankNo (BankNo)             
    }
}
function checkEnterForFindListing(e){
    var characterCode;
   
    if(e && e.which){
        e = e;
        characterCode = e.which ;
    }
    else{
        e = event;
        characterCode = e.keyCode;
    }
   
    if(characterCode == 22){    
        document.forms[getNetuiTagName("findListingForm")].submit();
        return false;
    }
    else{
        return true ;
    }
}
</script>
<input type="text" value="" size="25" onkeyup="formatBankNo(this)" onkeydown="formatBankNo(this)" name="account" id="account">