Prompt for code name when entering a HTML page

I am trying to prompt users to enter a code in order to get into my website. The problem is I am using the following code but some of my us开发者_如何学Cer see the prompt window, instead there will be a flashing page. Is there a alternate way to do it?

<script type="text/javascript">
function show_prompt() {
    var txtcode = prompt("Please enter your code", "");
    txtcode.toLowerCase();
    if (txtcode != null && txtcode == "special") {
        confirm;
    }
    else {
        window.location = "http://happylemon.asp";
    }

}

Instead of a prompt, you should create a proper login page with a form that is submitted to the server and validated. If valid, the user can then be directed to the homepage.

If you use PHP, there are a ton of resources to help with creating a secure login: http://www.google.ca/search?aq=f&sourceid=chrome&ie=UTF-8&q=php+login+page

Why not make a regular authenticate page, but instead of username/password ask for the code? Then submit to server and compare there.

It's NOT safe to put your secret code in Javascript.

There are some typing errors:

I am trying to prompt users to enter a code in order to get into my website.

Should be

I want to keep visitors away from my website.

Just create a normal login page with a login form, and validate the data on the server. No need to ugly (and completely useless) authentication pop-ups.