Q:

Cookie alert at bottom

I want a alert at the bottom of the screen that says that the website is using cookies (and it only needs to be shown to new users).  It needs to stay at the bottom if you scroll down too.  I don't know how to do it, because I am a self-learning person and I am just starting learning how to code. 
Thanks for the help. 

A:

Part 1 : HTML & CSS
We need to add the alert panel into the bottom of the page.  for styling this panel we should use CSS.  this panel also has the confirmation button.  if user click button we set the cookie to browser and never show the panel again.  
<div class="bottom" id="alert">
  this website use cookies
  <button onclick="accpetCookie()">
    click here for accpet cookie
 </button>
</div>
<div class="scroll">
  website content
</div>

for setting style we create CSS class 
.bottom {
  position: fixed;
  bottom: 0;
  width: 100%;
  background: #ccc;
  color: #fff
}

.scroll {
  min-height: 1500px;
}

Part 2 : Javascript
    <script>
    // if user has already checked the confirmation button
    // the alert panel should be hidden.    
    if (getCookie('accepted') === 'yes') {
        document.getElementById("alert").style.display = "none";
    }

    // user clicks the confirmation -> set the 'yes' value to cookie and set 'accepted' as name
    function accpetCookie() {
        setCookie('accepted', 'yes', 100);
    }

    // code from :http://stackoverflow.com/a/4825695/191220
    // set cookie method
    function setCookie(c_name, value, exdays) {
        var exdate = new Date();
        exdate.setDate(exdate.getDate() + exdays);
        var c_value = escape(value) + ((exdays == null) ? "" : ";  expires=" + exdate.toUTCString());
        document.cookie = c_name + "=" + c_value;
    }

    // get cookie method   
    function getCookie(c_name) {
        var i, x, y, ARRcookies = document.cookie.split(";");
        for (i = 0; i < ARRcookies.length; i++) {
            x = ARRcookies[i].substr(0, ARRcookies[i].indexOf("="));
            y = ARRcookies[i].substr(ARRcookies[i].indexOf("=") + 1);
            x = x.replace(/^\s+|\s+$/g, "");
            if (x == c_name) {
                return unescape(y);
            }
        }
    }
</script>

check the Jsfiddle page for live demo.