Which tag is used to add definition lists into a <dl> element?

<dl>
 <dt>HTML</dt>
  <dd> - Hyper Text Markup Language</dd>
  <dd> - Language for web pages</dd>
</dl>

Which CSS property can hide an element on page, letting an empty space in its place?

display position visibility

#id {
  visibility: hidden;
}

Click on the event which is triggered when the mouse clicks on an object.

onclick onmouseover onfocus

document.getElementById("id").onclick = function(){
  alert("http://CoursesWeb.net/");
}

Indicate the PHP variable that contains the contents of both $_GET, $_POST, and $_COOKIE arrays.

$_SESSION $_GET $_REQUEST

if(isset($_REQUEST["id"])) {
  echo $_REQUEST["id"];
}

Actionscript/css Course