TutorBoy » Sreejith Sreedharan

Creating a simple fade over effect – JQuery

Sreejith Sreedharan — Tue, 09 Mar 2010 12:48:20 +0000

Here , i will tell you how to add a fade over /fade in effect to image button in jquery. its very simple……………………………

1. Import jquery

2. Add a div tag with image in it

3 . Add script Jquery on load

$(document).ready(function(){
 $("img").hover(
 function() {
 $(this).animate({"opacity": "0"}, "slow");
 },
 function() {
 $(this).animate({"opacity": "1"}, "slow");
 }
 );
});

That’s it . you can now see the fade in and fade out effect on mouse over the button
you can change the js to add more functionalites.

Type Casting in Java

Sreejith Sreedharan — Fri, 05 Mar 2010 09:51:16 +0000

In any Object oriented programming language , one object reference can be type cast into another object reference.

There are compile-time rules and runtime rules for casting in java

There can be 2 casting java scenarios ·

Upcasting
Downcasting

When we cast a reference along the class hierarchy in a direction from the root class towards the children or subclasses, it is a downcast. When we cast a reference along the class hierarchy in a direction from the sub classes towards the root, it is an upcast. We need not use a cast operator in this case. The compile-time rules are there to catch attempted casts in cases that are simply not possible. This happens when we try to attempt casts on objects that are totally unrelated (that is not subclass super class relationship or a class-interface relationship) At runtime a ClassCastException is thrown if the object being cast is not compatible with the new type it is being cast to.

Below is an example showing when a ClassCastException can occur during object casting

Java Code

//X is a supper class of Y and Z which are sibblings.
public class RunTimeCastDemo {

	public static void main(String args[]) {
		X x = new X();
		Y y = new Y();
		Z z = new Z();
		X xy = new Y(); // compiles ok (up the hierarchy)
		X xz = new Z(); // compiles ok (up the hierarchy)
		//		Y yz = new Z();   incompatible type (siblings)
		//		Y y1 = new X();   X is not a Y
		//		Z z1 = new X();   X is not a Z
		X x1 = y; // compiles ok (y is subclass of X)
		X x2 = z; // compiles ok (z is subclass of X)
		Y y1 = (Y) x; // compiles ok but produces runtime error
		Z z1 = (Z) x; // compiles ok but produces runtime error
		Y y2 = (Y) x1; // compiles and runs ok (x1 is type Y)
		Z z2 = (Z) x2; // compiles and runs ok (x2 is type Z)
		//		Y y3 = (Y) z;     inconvertible types (siblings)
		//		Z z3 = (Z) y;     inconvertible types (siblings)
		Object o = z;
		Object o1 = (Y) o; // compiles ok but produces runtime error
	}
}

Creating a simple popup

Sreejith Sreedharan — Tue, 02 Mar 2010 06:11:13 +0000

This tutorial will guide you create a simple popup based on CSS and Javascript

1. Create a simple div

HTML

here , make sure you put z-index to a value , display to none and position as absoulte.

2. Write Open PopUP and Close PopUp in javascript

Javascript

// for popup Open
function popupwindowOpen()
{
document.getElementById('overlayContent').style.display = "block";

}
// for popup close
function popupwindowClose()
{
document.getElementById('overlayContent').style.display = "none";
}

That’s all………. this is a simple popup . you can add extra features to it..ex:apply CSS
and it will look good.