If you want the visitor to accept before he / she goes on...:

I accept:

Put this between your HEAD-tags

<SCRIPT LANGUAGE="JavaScript"> <!-- Begin function checkCheckBox(f){ if (f.agree.checked == false ) { alert('Please check the box to continue.'); return false; }else return true; } // End --> </script>

Put this where you want the form:

<form action="/yourscript.cgi-or-your-page.html" method="POST" onsubmit="return checkCheckBox(this)"> I accept: <input type="checkbox" value="0" name="agree"> <input type="submit" value="Continue"> <input type="button" value="Exit" onclick="document.location.href='/index.html';"> </form>