How to make fixed header table inside scrollable div?

Using position: sticky on th will do the trick.

Note: if you use position: sticky on thead or tr, it won't work.

https://jsfiddle.net/hrg3tmxj/

How about doing something like this? I've made it from scratch...

What I've done is used 2 tables, one for header, which will be static always, and the other table renders cells, which I've wrapped using a div element with a fixed height, and to enable scroll, am using overflow-y: auto;

Also make sure you use table-layout: fixed; with fixed width td elements so that your table doesn't break when a string without white space is used, so inorder to break that string am using word-wrap: break-word;

Demo

.wrap {
    width: 352px;
}

.wrap table {
    width: 300px;
    table-layout: fixed;
}

table tr td {
    padding: 5px;
    border: 1px solid #eee;
    width: 100px;
    word-wrap: break-word;
}

table.head tr td {
    background: #eee;
}

.inner_table {
    height: 100px;
    overflow-y: auto;
}

<div class="wrap">
    <table class="head">
        <tr>
            <td>Head 1</td>
            <td>Head 1</td>
            <td>Head 1</td>
        </tr>
    </table>
    <div class="inner_table">
        <table>
        <tr>
            <td>Body 1</td>
            <td>Body 1</td>
            <td>Body 1</td>
        </tr>
        <!-- Some more tr's -->
    </table>
    </div>
</div>