A key feature of Web authoring software is the ability to layout semantic web design using CSS inspectors and tools. A CSS page layout uses the Cascading Style Sheets format, rather than traditional HTML tables or frames, to organize the content on a web page. The basic building block of the CSS layout is the "div tag"—an HTML tag that in most cases acts as a container for text, images, and other page elements. When you create a CSS layout, you place div tags on the page, add content to them, and position them in various places. Unlike table cells, which are restricted to existing somewhere within the rows and columns of a table, div tags can appear anywhere on a web page. Website developers position div tags by specifying floats, paddings, and margins, the preferred methods by today’s web standards.
Commercial Web authoring software (for instance Dreamweaver CS6) eliminates having to make CSS layouts from scratch. This may be very desirable because unaided CSS layout can be very time-consuming and be difficult because there are so many ways to do it. Simple two-column CSS layout may be accomplished by setting floats, margins, paddings, and other CSS properties in a nearly infinite number of combinations. CSS layouts made from scratch will not display properly in some browsers. Dreamweaver allows the building of pages with CSS layouts by providing 16 pre-designed layouts that work across different browsers.