onmouseover

 
<!DOCTYPE HTML>
<html>
<head>
<title>Example</title>
<style type="text/css">
p {
  background: gray;
  color: white;
  padding: 10px;
  margin: 5px;
  border: thin solid black
}
</style>
<script type="text/javascript">
  function handleMouseOver(elem) {
    elem.style.background = 'white';
    elem.style.color = 'black';
  }
  function handleMouseOut(elem) {
    elem.style.removeProperty('color');
    elem.style.removeProperty('background');
  }
</script>
</head>
<body>
  <p onmouseover="handleMouseOver(this)"
    onmouseout="handleMouseOut(this)">
    This is a test. 
  </p>
  <p onmouseover="handleMouseOver(this)"
    onmouseout="handleMouseOut(this)">
    This is a test. 
  </p>
</body>
</html>
Click to view the demo