Basics of HTML, CSS, & JS

HTML & CSS

structural markup: structural elements, e.g. elements for headings and paragraphs
semantic markup: markup to convey additional meaning, e.g. <strong>, <em>, etc.
6 levels of headings <h1> (main heading) through <h6>
<p> are shown on a new line by default
<sup> = superscript, used commonly for suffixes or math
<sub> = subscript, used commonly for footnotes
white space collapsing = browsers display 2+ sequential spaces as a single white space.
<br /> = linebreak
<hr />= horizonal line linebreak, can be used to divide sections

<strong> = strong importance, text will show in bold
<em> = emphasis, text will show in italics
<blockquote> = used for long quotes, still requires the <p> tag for quote text
<q> = used for short quotes, Internet Explorer does not put quotes around <q> tags
<abbr> = used for abbreviations, uses a title attribute for the full term that is being abbreviated. Syntax: <abbr title="full term">abbreviation</abbr>
<cite> = used to cite sources
<dfn> = defining instance, used when a new term is defined
<address> = used for contact info for author of the webpage
<ins> = underlines content added to a doc
<del> = crosses out content deleted from a doc
<s> = crosses out content that is not relevant but should remain in the doc, e.g. a change in price for an item

declare an unassigned variable if its value will be conditionally assigned (e.g. in an if/else statement)
data types: Numbers, Strings, Boolean
booleans true and false are lowercase
escape character: \ - use before quotes within a string if the quotes are part of the string
variables can start with letters, $, or _, but not numbers
cannot use - or . in a variable name
arrays are declared with a literal array: x = [values]; or with an array constructor: var x = new Array(values);
array indexing starts at 0
.textcontent = sets text of specified element along with all of its descendents