Bootstrap3 Tutorial


What is Bootstrap?

Bootstrap is set of css and javascript files that take css to a higher level of abstraction and makes responsive web sites easier to build.

Where to get Bootstrap3?

Visit to get the css and javascript files.

A great tutorial for Bootstrap 4 is

Basic Concepts

All bootstrap elements must be inside a "container" element, often a "div" tag, or the body element.

A container is a page level attribute and cannot be nested, but it is common to have a header container, a body container, and a footer container, but these cannot overlap.

A div with the class of ".container" will center content in center of viewport. A div with a class of ".container-fluid" will always takes up full width of browser or viewport.

Within the container are a series of "row" divs.

Within the "row" are 12 columns.

Visual Breakpoints

Visual breakpoints are how bootstrap arranges the 12 columns with different sizes of devices.

Breakpoint Pixel Width Name Devices
xs Extra-Small <768px phone
sm Small >=768pxtablet
md Medium >=992pxdesktop
lg Large >1200pxdesktop

Example of a class: If an element has a class of "col-sm-6", it means on small devices, and everything larger the element will be 6 columns wide. It has no effect on devices smaller than that, i.e., "xs".

Mulitple classes can be assigned to an element, for example, "col-sm-3 col-lg-5".

class="col-md-6 col-xs-12" to specify 6 columns on regular, but on phones take all 12

Meta-tags for devices

For bootstrap to work in the head section we need to include the viewport meta-tag, the JavaScript and the css files:

<!-- include Bootstrap libraries -->
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="">
  <script src=""></script>
  <script src=""></script>

Now inside the body we can create three columns in one row with widths of 2,8, and 2.

<div class="container-fluid"> <!-- main div -->
<div class="row">  <!-- row -->

<aside class="col-sm-2 leftPanel bordered" > <!-- left panel -->
<h1>Left Panel</h1>

<section class="col-sm-8 centerPanel bordered"> <!-- center panel -->
<h1>Center Panel</h1>

<section class="col-sm-2 rightPanel bordered"> <!-- right panel -->
<h1>Right Panel</h1>

</div>  <!-- row -->

Here is a very basic example of the "mostly fluid" pattern, it will simply stack all the sections when viewed on a xtra-small device (i.e., when the width is less than 768 pixels): Mostly Fluid, view it then right-click and "View Source".

To move columns around we use "push" and "pull" classes. For example, "col-sm-pull-8" will pull the column to the left 8 sections for everything larger than "sm" size.

To hide and entire column at the "sm" size, we use the "hidden-sm". To make then visible use "visible-sm". For example, to hide a column only on phones use these classes: "hide-xs visible-sm".

Here is another example of the "mostly fluid" pattern, but instead of stacking, we will move columns: Mostly Fluid, view it then right-click and "View Source".

Responsive Navigation

An example Bootstrap navigation bar based on the one from is here.

Nav bar

And seen on a phone it looks like this:

Nav bar on phone

Links and Other Items


To see how the page will look in various devices use the developer extension in Chrome and select "command-option-i" on the mac and click on the little device icon at the upper-left.