Just insert the below script to the HEAD section of your page, and enter your list of IPs to block:
<script type="text/javascript">
//Enter list of banned ips, each separated with a comma:
var bannedips=["23.23.23.23", "11.11.11.11"]
var ip = '<!--#echo var="REMOTE_ADDR"-->'
var handleips=bannedips.join("|")
handleips=new RegExp(handleips, "i")
if (ip.search(handleips)!=-1){
alert("Your IP has been banned from this site. Redirecting...")
window.location.replace("http://www.google.com")
}
</script>