鼠标滑过display:none 变为 display:block
<div class="col" onmouseover="overShow()" onmouseout="outHide()">
<div id="content" class="img-thumbnail" style="display: none;">
<script>
function overShow(){
document.getElementById("content").style.display = "block";
}
function outHide(){
document.getElementById("content").style.display = "none";
}
</script>