Category: JavaScript Answers

Sometimes, we want to restart animation in CSS3 and JavaScript.

In this article, we’ll look at how to restart animation in CSS3 and JavaScript.

How to restart animation in CSS3 and JavaScript?

To restart animation in CSS3 and JavaScript, we can get the offsetHeight property to trigger reflow.

For instance, we write

function resetAnimation() {
  const el = document.getElementById("animated");
  el.style.animation = "none";
  el.offsetHeight;
  el.style.animation = null;
}

const button = document.querySelector("button");
button.onclick = resetAnimation;

to create the resetAnimation function.

We get the element we want to animate with getElementById.

Then we get the offsetHeight to trigger reflow.

We clear el.style.animation by setting it to null.

Then we add our animation styles with

#animated {
  position: absolute;
  width: 50px;
  height: 50px;
  background-color: black;
  animation: bounce 3s ease-in-out infinite;
}

@keyframes bounce {
  0% {
    left: 0;
  }
  50% {
    left: calc(100% - 50px);
  }
  100% {
    left: 0;
  }
}

to set the animation styles of the element with ID animated.

And we add the elements with

<div id="animated"></div>
<button>Reset</button>

Conclusion

To restart animation in CSS3 and JavaScript, we can get the offsetHeight property to trigger reflow.

Sometimes, we want to extract filename from a file input control with JavaScript.

In this article, we’ll look at how to extract filename from a file input control with JavaScript.

How to extract filename from a file input control with JavaScript?

To extract filename from a file input control with JavaScript, we can get the file name with the name property.

For instance, we write

document.getElementById("imgName").onchange = (e) => {
  const [file] = e.target.files;
  const filename = file.name;
  //...
};

to get the file input with

document.getElementById("imgName")

Then we assign the onchange property to a function that gets the files select with e.target.files.

And then we get the first file with destructuring.

Then we get the file’s name with file.name.

Conclusion

To extract filename from a file input control with JavaScript, we can get the file name with the name property.

Sometimes, we want to set HTML5 audio position with JavaScript.

In this article, we’ll look at how to set HTML5 audio position with JavaScript.

How to set HTML5 audio position with JavaScript?

To set HTML5 audio position with JavaScript, we can set the currentTime property.

For instance, we write

const element = document.getElementById("audioPlayer");
element.play();
element.currentTime = 226;

to get the audio element with getElementById.

And then we set the currentTime property to the position of the audio in seconds.

Conclusion

To set HTML5 audio position with JavaScript, we can set the currentTime property.

Sometimes, we want to move the mouse pointer to a specific position with JavaScript.

In this article, we’ll look at how to move the mouse pointer to a specific position with JavaScript.

How to move the mouse pointer to a specific position with JavaScript?

To move the mouse pointer to a specific position with JavaScript, we can call requestPointerLock in the element.

For instance, we write

const canvas = document.getElementById('myCanvas');
canvas.requestPointerLock();

to get the canvas element with getElementById.

Then we call canvas.requestPointerLock to request permission to lock the mouse pointer in place.

Conclusion

To move the mouse pointer to a specific position with JavaScript, we can call requestPointerLock in the element.

Sometimes, we want to add property to an array of objects with JavaScript.

In this article, we’ll look at how to add property to an array of objects with JavaScript.

How to add property to an array of objects with JavaScript?

To add property to an array of objects with JavaScript, we can use the array map method.

For instance, we write

const mappedResults = results.map((obj) => ({ ...obj, active: false }));

to call results.map with a callback that returns new objects that has properties in the existing object being processed and the active property added to it.

A new array with the new objects are returned so we assign the returned array to mappedResults.

Conclusion

To add property to an array of objects with JavaScript, we can use the array map method.