Online.Report style
Published on Saturday, May 24, 1997 by Gideon ArielReport style templates
Report Style in APAS/Wizard is defined in Cascading Style Sheets (CSS)
- CSS stands for Cascading Style Sheets
- Styles define how to display HTML elements
- Styles are normally stored in Style Sheets
- Styles were added to HTML 4.0 to solve a problem
- External Style Sheets can save you a lot of work
- External Style Sheets are stored in CSS files
- Multiple style definitions will cascade into one
Styles Solve a Common Problem
HTML tags were originally designed to define the content of a document. They were supposed to say “This is a header”, “This is a paragraph”, “This is a table”, by using tags like <h1>, <p>, <table>, and so on. The layout of the document was supposed to be taken care of by the browser, without using any formatting tags.
As the two major browsers – Netscape and Internet Explorer – continued to add new HTML tags and attributes (like the <font> tag and the color attribute) to the original HTML specification, it became more and more difficult to create Web sites where the content of HTML documents was clearly separated from the document’s presentation layout.
To solve this problem, the World Wide Web Consortium (W3C) – the non profit, standard setting consortium responsible for standardizing HTML – created STYLES in addition to HTML 4.0.
Both Netscape 4.0+ and Internet Explorer 4.0+ support Cascading Style Sheets.
Style Sheets Can Save a Lot of Work
Styles in HTML 4.0 define how HTML elements are displayed, just like the font tag and the color attribute in HTML 3.2. Styles are normally saved in files external to your HTML documents. External style sheets enable you to change the appearance and layout of all the pages in your Web, just by editing a single CSS document. If you have ever tried to change the font or color of all the headings in all your Web pages, you will understand how CSS can save you a lot of work.
CSS is a breakthrough in Web design because it allows developers to control the style and layout of multiple Web pages all at once. As a Web developer you can define a style for each HTML element and apply it to as many Web pages as you want. To make a global change, simply change the style, and all elements in the Web are updated automatically.
Multiple Styles Will Cascade Into One
Style Sheets allow style information to be specified in many ways. Styles can be specified inside a single HTML element, inside the <head> element of an HTML page, or in an external CSS file. Even multiple external Style Sheets can be referenced inside a single HTML document.
Cascading Order
What style will be used when there is more than one style specified for an HTML element?
Generally speaking we can say that all the styles will “cascade” into a new “virtual” Style Sheet by the following rules, where number four has the highest priority:
- Browser default
- External Style Sheet
- Internal Style Sheet (inside the <head> tag)
- Inline Style (inside HTML element)
So, an inline style (inside an HTML element) has the highest priority, which means that it will override every style declared inside the <head> tag, in an external style sheet, and in a browser (a default value).
Syntax
The CSS syntax is made up of three parts: a selector, a property and a value:
selector {property: value} |
The selector is normally the HTML element/tag you wish to define, the property is the attribute you wish to change, and each property can take a value. The property and value are separated by a colon and surrounded by curly braces:
body {color: black} |
If the value is multiple words, put quotes around the value:
p {font-family: "sans serif"} |
Note: If you wish to specify more than one property, you should separate each property with a semi-colon. The example below shows how to define a center aligned paragraph, with a red text color:
p {text-align:center;color:red} |
To make the style definitions more readable, you can describe one property on each line, like this:
Grouping
The class Selector
With the class selector you can define different styles for the same type of HTML element. Say that you would like to have two types of paragraphs in your document: one right-aligned paragraph, and one center-aligned paragraph. Here is how you can do it with styles:
You have to use the class attribute in your HTML document:
Note: Only one class attribute can be specified per HTML element! The example below is wrong:
You can also omit the tag name in the selector to define a style that will be used by all HTML elements that have a certain class. In the example below, all HTML elements with class=”center” will be center-aligned:
In the code below both the h1 element and the p element have class=”center”. This means that both elements will follow the rules in the “.center” selector:
The id Selector
The id selector is different from the class selector! While a class selector may apply to SEVERAL elements on a page, an id selector always applies to only ONE element.
An ID attribute must be unique within the document.
The style rule below will match a p element that has the id value “para1”:
The style rule below will match the first element that has the id value “wer345”:
The style rule below will match the first element that has the id value “wer345”:
The style rule below will match a p element that has the id value “wer345”:
The rule above will not match this h2 element:
CSS Comments
You can insert comments in CSS to explain your code, which can help you when you edit the source code at a later date. A comment will be ignored by the browser. A CSS comment begins with “/*”, and ends with “*/”, like this:
/* This is a comment */
p
{
text-align: center;
/* This is another comment */
color: black;
font-family: arial
} |
Color names
On this page you will find a table of color names that are supported by newer versions of both Netscape and Internet Explorer.
Note: Color names are not supported by the W3C standards. If you want to write correct CSS you should use the Color HEX values.