Wordpress Help! Anyway to put a Splash screen for my Adult blog? 10$ Reward

Im using wordpress as a CMS For my adult site .Videos / Pictures / The works. I currently have no warning when users come in that the site is an adult site. Is there anyway I Can put a splash screen up when users first enter the site asking whether they're 18 or not? I don't want to change the homepage url as that may hurt SERPS, I think. I WILL PAY 10$ For anyone to help me set this up.

 

Make a file called index.html. It wont interfere with /index.php

 

And if people go directly to my URL, It'll access Index.html before it does Index.php?

 

<script language="javascript">
var agePrompt=prompt("You must be over 18 to enter.\n Please enter your age.")

if (agePrompt>=18)
document.location="http://yourpage.com";
else {
alert('Sorry, minors are not allowed in this section! \n You must be 18 years old to enter.')
document.location="http://www.cartoonnetwork.com/";

}
</script>

Code (markup):

Try the above code.

 

That works, but its a bit annoying. I would try something with cookies so it can remember what options it chose.

 

It doesn't work, as it people click the header, It links right back to my site , and they'll have to enter the 18 age thing again. Anyway to use a similar script with cookies so it only asks once, even if you hit the main page multiple times? Remember, 10$ For whoever helps me implement it.