Div adjust to table size - html

Question

I have an html table with some rows, this table is inside an HTML div, I need this div to always have a scroll.
In order to do this, I am setting this two properties in the css of the div: height: 400px and overflow-y: scroll, yet, as you may know, the scroll only appears when the table exceeds the size of 400px.
Is there anyway to make the div always have a size slightly smaller than the table (for example, for the div to be 90% of the size of the table), or any other way to make the div always have the scroll?
#events_div{
height:400px;
overflow-y:scroll
}
<div id="events_div">
<table id="events_table">
<thead>
<th>...</th>
</thead>
<tbody>
<tr>
<td>...</td>
</tr>
</tbody>
</table>
</div>

Answer 1

set the min-height values of each and that should accomplish what you want.

Answer 2

Using jQuery of JavaScript, you can get the height of the table and set the div to be slightly smaller than the width you retrieved from the table. Be sure run this code only when the page has fully loaded (see code for jQuery):
$(document).ready(function() {
// put your code here
});
Another solution would be to set the height of the table to 105% (some value above 100). This only works if the parent div that surrounds the table has a predefined height.

Answer 3

All you need to do is set the max-height of your div to something smaller than the projected height of the table. So if the table is going to be about 300px tall set your div's max-height: 200px;
.theDiv {
max-height: 200px;
overflow-y: scroll;
background: blue;
}
.theTable {
height: 300px;
background: black;
color: white;
}
<div class="theDiv">
<table class="theTable">
<tr>
<th>Hello</th>
</tr>
<tr>
<td>Hello person</td>
</tr>
</table>
</div>
Also if you don't know the height of your table, set the min-height to something larger than the height of your div.