201-reading-notes

this is where i keep my 201 notes

# MARKUP

When creating a web page, you add tags (known as markup) to the contents of the page. These tags provide extra meaning and allow browsers to show users the appropriate structure for the page.
STRUCTURAL MARKUP: the elements that you can use to describe both headings and paragraphs
SEMATIC MARKUP: which provides extra information; such as where emphasis is placed in a sentence, that something you have written is a quotation (and who said it), the meaning of acronyms, and so on.

## Superscript & Subscript

^{The ^{element is used to contain characters that should be superscript such
as the suffixes of dates or mathematical concepts like raising a number to a power such as 22.}}
_{The _{element is used to contain characters that should be subscript. It is commonly
used with foot notes or chemical formulas such as H20.}}

## Quotations

The
element is used for longer quotes that take up an entire paragraph. Note how the
element is still used inside the
element. Browsers tend to indent the contents of the
element, however you should not use this element just to indent a piece of text — rather you should achieve this effect using CSS.
The element is used for shorter quotes that sit within a paragraph. Browsers are supposed to put quotes around the element, however Internet Explorer does not — therefore many people avoid using the element. Both elements may use the cite attribute to indicate where the quote is from.

## CSS Associates Style rules with HTML elements

CSS works by associating rules with HTML elements. These rules govern how the content of specified elements should be displayed. A CSS rule contains two parts: a selector and a declaration.

CSS Properties Affect How Elements Are Displayed
CSS declarations sit inside curly brackets and each is made up of two parts: a property and a value, separated by a colon. You can specify several properties in one declaration, each separated by a semi-colon.

## How Css Rules Cascade

If there are two or more rules that apply to the same element, it is important to understand which will take precedence.
LAST RULE If the two selectors are identical, the latter of the two will take precedence. Here you can see the second i selector takes precedence over the first.
SPECIFICITY If one selector is more specific than the others, the more specific rule will take precedence over more general ones. In this example: h1 is more specific than * p b is more specific than p p#intro is more specific than p
IMPORTANT You can add !important after any property value to indicate that it should be considered more important than other rules that apply to the same element. Understanding how CSS rules cascade means you can write simpler style sheets because you can create generic rules that apply to most elements and then override the properties on individual elements that need to appear differently.

A script will have to temporarily store the bits of information it needs to do its job. It can store this data in variables. When you write JavaScript, you have to tell the interpreter every individual step that you want it to perform. This sometimes involves more detail than you might expect. Think about calculating the area of a wall; in math the area of a rectangle is obtained by multiplying two numbers: width x height = area You may be able to do calcula tions like this in your head, bu t when writing a script to do this calculation, you need to give the computer very detailed instructions. You might tell it to perform the following four steps in order:
1. Remember the value for width
2. Remember the value for height
3. Multiply width by height to get the area
4. Return the result to the user In this case, you would use vari ables to “remember” the va lues for width and height. (This also illustrates how a scrip( contains very explicit instructions about exactly what you want the computer to do.) You can compare variables to short-term memory, because once you leave the page, the browser will forget any information it holds.
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