Answers for "on hover function javascript"

javascript hover event

element.onmouseover = function() {
  //Hovering
}

hover con js

// Creamos el evento mouseover para cada imagen
	imagenes[i].addEventListener("mouseover", function(e){
		document.getElementById("mostrar").style.backgroundImage="url('"+e.target.currentSrc+"')";
	});
 
// Creamos el evento mouseout para cada imagen
imagenes[i].addEventListener("mouseout", function(e){
  document.getElementById("mostrar").style.backgroundImage="";
});

javascript on hover

<img onmouseover="enlargeImage(this)" border="0" src="smiley.gif" alt="Smiley" width="32" height="32">

<script>
function enlargeImage(x) {
  x.style.height = "64px";
  x.style.width = "64px";
}
</script>