Style Preecedencr in CSS : Specificity, Inheritance and Cascade

CSS rule applies to a given html element is controled by

• Specificity Calculations
• Inheritance
• The Cascade

Specificity Calculations

Specificity is calculated by counting various components of your css and expressing them in a form (a,b,c,d). This will be clearer with an example, but first the components.

• Element, Pseudo Element: d = 1 – (0,0,0,1)
• Class, Pseudo class, Attribute: c = 1 – (0,0,1,0)
• Id: b = 1 – (0,1,0,0)
• Inline Style: a = 1 – (1,0,0,0)

An id is more specific than a class is more specific than an element.
It’s also important to note that 0,0,1,0 is more specific than 0,0,0,15.

Let’s look at the example

div p.bio {font-size: 14px} - (0,0,1,2)
#sidebar p {font-size: 12px} - (0,1,0,1)

The second has the higher specificity and thus takes precedence.
Importance trumps specificity, When you mark a css property with !important you’re overriding specificity rules and so

div p.bio {font-size: 14px !important}
#sidebar p {font-size: 12px}

means the first line of css above takes precedence instead of the second. !important is still mostly a hack around the basic rules and is something you should never need if you understand how the rules work.

Inheritance

Elements inherit styles from their parent container. If you set the body tag to use color: red then the text for all elements inside the body will also be red unless otherwise specified.

Not all css properties are inherited, though. For example margins and paddings are non-inherited properties. If you set a margin or padding on a div, the paragraphs inside that div do not inherit the margin and padding you set on the div. The paragraph will use the default browser margin and padding until you declare otherwise.

You can explicitly set a property to inherit styles from it’s parent container, though. For example you could declare

p {margin: inherit; padding: inherit}

and your paragraph would then inherit both from it’s containing element.

The Cascade

At the highest level the cascade is what controls all css precedence and works as follows.

1. Find all css declarations that apply to the element and property in question.
2. Sort by origin and weight. Origin refers to the source of the declaration (author styles, user styles, browser defaults) and weight refers to the importance of the declaration. (author has more weight than user which has more weight than default. !importance has more weight than normal declarations)
3. Calculate specificity
4. If two rules are equal in all of the above, the one declared last wins. CSS embedded in the html always come after external stylesheets regardless of the order in the html

#3 above is likely the one you’ll need to pay attention to most.
#2 just understand that your styles will override how a user sets their browser unless they set their rules to be important.

Play with Matrix using JavaScript

Demo : Play with Matrix using JavaScript

JSP Implicit Objects

Implicit objects in jsp are the objects that are created by the container automatically.Since these objects are created automatically by the container and are accessed using standard variables; hence, they are called implicit objects. The implicit objects are parsed by the container and inserted into the generated servlet code. They are available only within the jspService method and not in any declaration. Implicit objects are used for different purposes. Our own methods (user defined methods) can't access them as they are local to the service method and are created at the conversion time of a jsp into a servlet. But we can pass them to our own method if we wish to use them locally in those functions.

Objebt	Class
application	javax.servlet.ServletContext
config	javax.servlet.ServletConfig
exception	java.lang.Throwable
out	javax.servlet.jsp.JspWriter
page	java.lang.Object
PageContext	javax.servlet.jsp.PageContext
request	javax.servlet.ServletRequest
response	javax.servlet.ServletResponse
session	javax.servlet.http.HttpSession

• Application: These objects has an application scope. These objects are available at the widest context level, that allows to share the same information between the JSP page's servlet and any Web components with in the same application.
  
• Config: These object has a page scope and is an instance of javax.servlet.ServletConfig class. Config object allows to pass the initialization data to a JSP page's servlet. Parameters of this objects can be set in the deployment descriptor (web.xml) inside the element . The method getInitParameter() is used to access the initialization parameters.
  
• Exception: This object has a page scope and is an instance of java.lang.Throwable class. This object allows the exception data to be accessed only by designated JSP "error pages."
  
• Out: This object allows us to access the servlet's output stream and has a page scope. Out object is an instance of javax.servlet.jsp.JspWriter class. It provides the output stream that enable access to the servlet's output stream.
  
• Page: This object has a page scope and is an instance of the JSP page's servlet class that processes the current request. Page object represents the current page that is used to call the methods defined by the translated servlet class. First type cast the servlet before accessing any method of the servlet through the page.
  
• Pagecontext: PageContext has a page scope. Pagecontext is the context for the JSP page itself that provides a single API to manage the various scoped attributes. This API is extensively used if we are implementing JSP custom tag handlers. PageContext also provides access to several page attributes like including some static or dynamic resource.
  
• Request: Request object has a request scope that is used to access the HTTP request data, and also provides a context to associate the request-specific data. Request object implements javax.servlet.ServletRequest interface. It uses the getParameter() method to access the request parameter. The container passes this object to the _jspService() method.
  
• Response: This object has a page scope that allows direct access to the HTTPServletResponse class object. Response object is an instance of the classes that implements the javax.servlet.ServletResponse class. Container generates to this object and passes to the _jspService() method as a parameter.
  
• Session: Session object has a session scope that is an instance of javax.servlet.http.HttpSession class. Perhaps it is the most commonly used object to manage the state contexts. This object persist information across multiple user connection.

Database : May I help u????

Select Top N records..........

Microsoft SQL Server

SELECT TOP 10 column FROM table

MySQL

SELECT column FROM table LIMIT 10

Oracle

SELECT column FROM table WHERE ROWNUM <= 10

DB2

SELECT column FROM table
FETCH FIRST 10 ROWS ONLY