How to add special effects in javascript

JavaScript is a scripting language widely used in website development that can add excellent dynamic effects to a simple static HTML web page. With JavaScript, you can animate elements on your page, create visual interactions and user experiences, and enhance the appearance and functionality of your web pages.

In this article, we will introduce how to use JavaScript to add special effects to your web pages, as well as some common special effects implementation methods.

1. Dynamic effects

JavaScript can be used to create many dynamic effects, the most common of which is animation. Unlike CSS animations, creating animations with JavaScript gives you more control over the animation, such as changing the animation's speed, direction, pause and resume, and more.

The following are some methods of creating animations:

1. setInterval() function

setInterval() function is used to execute repeatedly within a specified time interval a specified function.

For example, the following code will make an element move horizontally on the page:

var element = document.getElementById("myElement");

var position = 0;
var id = setInterval(frame, 10);

function frame() {
  if (position == 350) {
    clearInterval(id);
  } else {
    position++;
    element.style.left = position + 'px';
  }
}

Every 10 milliseconds, setInterval() will call frame(), and in each call, the position of The value will increase by 1 until the element moves to a position of 350 pixels. setInterval() stops once the element reaches the specified position.

2. requestAnimationFrame() function

The requestAnimationFrame() function is a powerful animation function that uses the browser's rendering loop to control the speed and quality of animation. It calls the specified function before each redraw based on the screen refresh rate.

The following is an example of using requestAnimationFrame() to create animation:

var element = document.getElementById("myElement");
var position = 0;

function animate() {
  position++;
  element.style.left = position + 'px';
  
  if (position < 350) {
    window.requestAnimationFrame(animate);
  }
}

window.requestAnimationFrame(animate);

In the above code, whenever the animate() function is called, the value of position will be increased by 1, and the element's The left property will be set to the value of position. If the value of position is less than 350, requestAnimationFrame() will call animate() again before the next redraw.

2. Outline and shadow effects

When designing web pages, you may need to use outline and shadow effects to enhance the visual effect of your web page. Here are some common ways to create outlines and shadows using JavaScript.

1. box-shadow property

The box-shadow property creates a shadow effect for HTML elements. We can use JavaScript to dynamically change the color, size, position, or blur of a shadow effect. For example, the following code will add a shadow to the lower right corner of an element:

var element = document.getElementById("myElement");
element.style.boxShadow = "10px 10px 5px #888888";

where 10px and 5px represent the horizontal and vertical offsets of the shadow respectively, and #888888 is the color of the shadow.

2. outline attribute

The outline attribute creates an outline effect for HTML elements. We can also use JavaScript to dynamically adjust the color, size, style and offset of the outline. For example, the following code will add a red dashed border to an element:

var element = document.getElementById("myElement");
element.style.outline = "2px dashed red";

where 2px and dashed represent the width and style of the outline respectively.

3. Fade in and fade out effect

Fade in and fade out is a common animation effect, which is achieved by dynamically changing the transparency of elements. Here are some common ways to implement fades using JavaScript.

1. Use the opacity attribute

The opacity attribute sets the transparency of an element, with a value ranging from 0 to 1. By increasing or decreasing the value of opacity, we can create a fade effect for an element. For example, the following code will add a fade-in effect to an element:

var element = document.getElementById("myElement");
var opacityValue = 0;

var id = setInterval(frame, 10);

function frame() {
  if (opacityValue >= 1) {
    clearInterval(id);
  } else {
    opacityValue += 0.01;
    element.style.opacity = opacityValue;
  }
}

In the above code, we use setInterval() to periodically execute a function that changes the value of the element's opacity attribute. On each execution, the element's opacity value is increased by 0.01 until its value reaches 1. This creates a fade-in effect.

2. Using the jQuery Library

The jQuery library is a widely used JavaScript library that provides an easy-to-use set of APIs for quickly creating animation effects. The following is a sample code that uses jQuery to create a fade effect:

$("#myElement").fadeOut(1000, function() {
  $(this).fadeIn(1000);
});

In the above code, we use the fadeOut() and fadeIn() functions, which add fade-out and fade-in effects to the element respectively. 1000 represents the animation. The duration is 1 second.

4. Conclusion

In this article, we introduced some methods of using JavaScript to create web page special effects, including dynamic effects, contour and shadow effects, fade-in and fade-out effects, etc. By using these technologies, you can add fun and interactivity to your web pages and improve the user experience.

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