1. CS3220 Web and Internet Programming Page Layout with CSS
Chengyu Sun
California State University, Los Angeles

2. Regular HTML Page Layout
The elements “flows” from left to right and top to bottom

3. Some Page Layouts We May Want

4. Using CSS Over Table for Layouts?
Separation of structure and presentation
Better readability
Easier to change and maintain
More flexible and powerful
Accessibility support
Better performance

5. Example
Header
Menu
Content
Footer

6. The float Property
An element is taken out of the normal flow and placed along the left or right side of its container
The content of the other elements will wrap around the floated element

7. A float Example
float: left;

8. The clear Property
Whether an element can be next to floating elements that precede it or must be moved down below them
left: no floating elements on the left
right: no floating elements on the right
both: no floating elements on either side

9. A clear Example
clear: left;

10. The Positional Properties …
position – how an element is positioned
static: normal position
absolute: relative to the containing block
fixed: relative to the browser window
relative: relative to the normal position

11. … The Positional Properties
top, bottom, left, right – the positions of the top, bottom, left, and right side of the element
z-index
An element with higher z-index is displayed in front of elements with lower z-index
Only works on positioned elements

12. CSS Layout Modes Block layout Inline layout Table layout
float; multiple columns
Inline layout
Table layout
Positioned layout
Flexible box (i.e. flexbox) layout
Grid layout (experimental)

13. Multiple Columns Example
Mostly designed for displaying text
Properties
column-count
column-width (suggested optimal width)
column-gap
column-rule

14. Flexbox Example display: flex; flex-direction flex-wrap align-items
align-content and justify-content

15. About Responsive Web Design (RWD) …
Motivation
It’s important that a website looks good on mobile devices
It’s undesirable to create separate designs for different devices
Responsive Web Design – design website that automatically adapts to different viewing environments

16. … About Responsive Web Design (RWD)
A RWD example: The Boston Globe
What’s required: CSS, JavaScript, layout patterns (e.g. some grid system)
Libraries
Bootstrap
Material Design Lite (MDL)
And many more