<!DOCTYPE html>
<div style="width:800px; border: 0px solid blue;"><div style="border:2px solid red; float: left; width:550px">(Parent DIV have no border set) There should be a green table below this block</div><table style="border:2px solid green; width:100%;"><td>test</td></table></div><br>
<div style="width:800px; border: 2px solid blue;"><div style="border:2px solid red; float: left; width:550px">(Parent DIV have 2px blue border set)  There should be a green table below this block</div><table style="border:2px solid green; width:100%;"><td>test</td></table></div>