mixing DIV { display: block } and { display: block; float: left } * HTML4 Strict

{ display: block } element containing { display: block; float: left } element and one normal DIV { display: block }, centered, with Green background

beginning of text inside placeholder block

LightBlue background

	
	   float: left;
	   border: 15px solid;
	   height: 100px;
	   width: 100px;

Green background


	   border: 15px solid;
	   height: 100px;
	   width: 100px;
	   margin-left: auto;
	   margin-right: auto;

Some text inside placeholder, to show vertical and horizontal formatting.