<div class="box">
<div class="child">
</div>
<div class="child">
<div class="child_2">
</div>
</div>
</div><div class="box">
<div id="test">
<div></div>
</div>
</div>.box div:hover
$_FILES["file"]["size"] < 20000$extension = strtolower(end(explode(".", $_FILES["file"]["name"])));