Category: JavaScript Answers

Sometimes, we want to check if an element is really visible with JavaScript.

In this article, we’ll look at how to check if an element is really visible with JavaScript.

How to check if an element is really visible with JavaScript?

To check if an element is really visible with JavaScript, we can check if the element’s clientHeight is bigger than 0.

For instance, we write

const isViewable = (element) => {
  return element.clientHeight > 0;
};

to create the isViewable function to check if element.clientHeight is bigger than 0.

If clientHeight is bigger than 0, then the element is visible since clientHeight includes padding and margin.

Conclusion

To check if an element is really visible with JavaScript, we can check if the element’s clientHeight is bigger than 0.

Sometimes, we want to split a long array into smaller arrays with JavaScript.

In this article, we’ll look at how to split a long array into smaller arrays with JavaScript.

How to split a long array into smaller arrays with JavaScript?

To split a long array into smaller arrays with JavaScript, we can use the array splice method.

For instance, we write

const a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];
const b = a.splice(0, 10);

to call splice with 0 and 10 to remove the first 10 items from array a and return them in a new array.

Therefore, a is [11, 12, 13, 14, 15] and b is [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] after calling a.splice.

Conclusion

To split a long array into smaller arrays with JavaScript, we can use the array splice method.

Sometimes, we want to get scroll bar width using JavaScript.

In this article, we’ll look at how to get scroll bar width using JavaScript.

How to get scroll bar width using JavaScript?

To get scroll bar width using JavaScript, we can subtract the scrolling element’s width by the immediate child’s width.

For instance, we write

const child = document.querySelector("div");
const scrollbarWidth = child.parentNode.offsetWidth - child.offsetWidth;

to get the scroll container’s width with child.parentNode.offsetWidth .

Then we get the child div’s width with child.offsetWidth.

And then we subtract the scroll container’s width with the div’s width to get the scroll bar’s width.

Conclusion

To get scroll bar width using JavaScript, we can subtract the scrolling element’s width by the immediate child’s width.

Sometimes, we want to set text area height automatically with JavaScript.

in this article, we’ll look at how to set text area height automatically with JavaScript.

How to set text area height automatically with JavaScript?

To set text area height automatically with JavaScript, we can create our own function to set the height when we type into the text area.

For instance, we write

const autoGrow = (e) => {
  e.target.style.height = "5px";
  e.target.style.height = e.target.scrollHeight + "px";
};

const textarea = document.querySelector("textarea");
textarea.oninput = autoGrow;

to create the autoGrow function that sets the height of the text area when we type in it.

We set style.height to change its height.

e.target is the text area since, we have

const textarea = document.querySelector("textarea");
textarea.oninput = autoGrow;

to listen for input events on the text area, which means autoGrow runs when we type in the text area.

Then we add the text area with

<textarea></textarea>

And we add

textarea {
  resize: none;
  overflow: hidden;
  min-height: 50px;
  max-height: 100px;
}

to disable resizing of the text area by the user with resize: none;.

Conclusion

To set text area height automatically with JavaScript, we can create our own function to set the height when we type into the text area.

Sometimes, we want to capture the right-click event in JavaScript.

In this article, we’ll look at how to capture the right-click event in JavaScript.

How to capture the right-click event in JavaScript?

To capture the right-click event in JavaScript, we can listen for the contextmenu event.

For instance, we write

el.addEventListener(
  "contextmenu",
  (ev) => {
    ev.preventDefault();
    //...
  },
  false
);

to call el.addEventListener with 'contextmenu' and an event handler to listen for right clicks with the event handler.

We call ev.preventDefault in the event handler to stop the default behavior for right clicks, which is to show the context menu.

Then we can do what we want with right clicks in the event handler since the rest of the event handler will run after preventDefault is called.

Conclusion

To capture the right-click event in JavaScript, we can listen for the contextmenu event.