Using hover function in Jquery

I have learned how to use a hover function in jquery.

<script type="text/javascript">
$(document).ready(function(){
$('Id or class name of a div').hover(function(){
$('Id or class name of a div(same name)').css('opacity','1');
},function(){
$('Id or class name of a div(samename)').css('opacity','0');
});
});
</script>