How to write animation in jquery

jQuery is a powerful JavaScript library that greatly simplifies the work of developers and designers. Among them, Jquery’s animation effect has become one of the most important elements in design. This article will introduce how to use jQuery to create animation effects.

1. jQuery animation effects

jQuery animation effects are generally implemented using the animate() function. It allows programmers to create transition animations on one or more CSS properties. The animate() function requires at least two parameters: the CSS property to be changed and the time of the change, with an optional third parameter specifying a function to be executed after completion.

The following example will demonstrate how to change the CSS properties of the element to create an animation effect:

$(document).ready(function(){
  $("button").click(function(){
    $("div").animate({left: '250px', opacity: '0.5'}, 2000);
  });
});

In the above example, when the button is clicked, the div element will move at a speed of 2000 milliseconds. Move it 250 pixels to the left and change the Opacity to 0.5.

2. jQuery’s animate() function

jQuery’s animate() function can input multiple parameters, including CSS properties, change duration, and functions.

The following example will demonstrate how to use the animate() function to change multiple CSS properties at the same time:

$(document).ready(function(){
  $("button").click(function(){
    $("div").animate(
      {
        left: '250px',
        opacity: '0.5',
        height: '150px',
        width: '150px'
      },
      2000
    );
  });
});

In the above example, we changed the position, transparency, height and width of the element at the same time . These changes will be completed within a duration of 2000 ms.

3. jQuery’s speed parameters

jQuery provides three default speed parameters: slow, normal and fast. We can also use numbers to specify speed values. The higher the number, the faster the animation will execute. The following example demonstrates how to use the speed parameter:

$(document).ready(function(){
  $("button").click(function(){
    $("div").animate({left: '250px'}, "slow");
    $("div").animate({opacity: '0.5'}, "normal");
    $("div").animate({height: '150px', width: '150px'}, "fast");
  });
});

The above example animates the element at slow, normal, and fast speeds.

4. jQuery’s callback function

When calling the animate() function, we can pass it a callback function. The callback function will be called immediately after the animate() function completes execution.

The following example demonstrates how to use the callback function:

$(document).ready(function(){
  $("button").click(function(){
    $("div").animate({
      left: '250px',
      opacity: '0.5'
    }, 2000, function() {
      alert("动画执行完毕!");
    });
  });
});

The above example calls an alert() function after the animate() function is executed.

5. jQuery’s Queue

jQuery uses a queue to store all functions to be executed. When we use the animate() function, the function actually adds a function to the queue. The queue operates on a first-in-first-out basis. So if we want to perform some other task after the animation is completed, we have to use a queue.

The following example demonstrates how to use queues to specify multiple animations:

$(document).ready(function(){
  $("button").click(function(){
    var div = $("div");
    div.animate({left: '250px'}, 2000);
    div.animate({top: '250px'}, 2000);
    div.animate({left: '0px'}, 2000);
    div.animate({top: '0px'}, 2000);
  });
});

The above example moves the element to the upper right corner and then returns it to the original position.

6. Clearing the queue of jQuery

If you want to clear the queue while the animation is running, you must use the clearQueue() function. It will remove any subsequent functions from the running animation.

The following example demonstrates how to clear the queue:

$(document).ready(function(){
   $("button").click(function(){
     $("div").animate({left: '500px'}, 5000);
     $("div").animate({opacity: '0.0'}, 3000);
     $("div").animate({top: '200px'}, 5000);
     $("div").clearQueue();
   });
});

The above example clears the queue when the movement reaches the middle, that is, the next animation will not be executed.

7. jQuery’s stop animation

If you want to stop a running animation, you can use the stop() function. For example, if we want to stop the above animation when a stop button is pressed, we can use it like this:

$("button").click(function(){
  $("div").stop();
});

8. Comprehensive Application

The following example demonstrates how to use mouse hover and Mouse removal events to start and stop the animation:

$(document).ready(function(){
  $("div").hover(function(){
    $(this).animate({left: '250px'});
  },
    function(){
    $(this).animate({left: '0px'});
  });
});

The above example will move the element 250 pixels to the right on mouseover, and return to the original position when the mouse is removed.

9. Summary

jQuery’s animate() function makes it very easy to create animation effects. Whether it is basic animation, multiple animations or callback functions, you can easily implement it. You only need to understand the basic operations and syntax of jQuery.

When designing animations, we need to judge which animation effects to use based on the needs of the website or application. We can add appropriate speed parameters at the beginning of the animation to provide a smooth user experience to the user. You can use callback functions and queues to perform any other operations during animation execution. At any time, you can use the stop() and clearQueue() functions to stop or clear the animation in the queue.

Finally, JQuery’s animation function is a necessary skill for designers, and it is also a powerful tool for realizing web page animation effects. I hope this article can help everyone better understand and apply animation special effects in jQuery.

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