类似以下内容:

<table>
<tr>
<td>
    <a href="/pdfs/test1.pdf" onmouseover="previewUrl(this.href,'div1')">google</a>
</td>
<td>
    <div id="div1" style="width:400px;height:200px;border:1px solid #ddd;"></div>
</td>
</tr>
</table>

<script>
    function previewUrl(url,target){
        //use timeout coz mousehover fires several times
        clearTimeout(window.ht);
        window.ht = setTimeout(function(){
            var div = document.getElementById(target);
            div.innerHTML = '<iframe style="width:100%;height:100%;" frameborder="0" src="' + url + '" />';
        },20);      
    }   
</script>