Category: JavaScript

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.

Sometimes, we want to force download of a base64 image with JavaScript.

in this article, we’ll look at how to force download of a base64 image with JavaScript.

How to force download of a base64 image?

To force download of a base64 image with JavaScript, we add the download attribute to the anchor element.

For instance, we write

<a href="data:image/jpeg;base64,/9j/4AAQSkZ..." download="filename.jpg">
  download
</a>

to add the anchor element with the href attribute set the base64 image URL.

And we add the download attribute and set it to the file name of the downloaded image to let users download the image when the link is clicked.

Conclusion

To force download of a base64 image with JavaScript, we add the download attribute to the anchor element.

Sometimes, we want to convert special characters to HTML in JavaScript.

In this article, we’ll look at how to convert special characters to HTML in JavaScript.

How to convert special characters to HTML in JavaScript?

To convert special characters to HTML in JavaScript, we can us the String.fromCharcode method.

For instance, we write

const decodeHtmlCharCodes = (str) =>
  str.replace(/(&#(\d+);)/g, (match, capture, charCode) =>
    String.fromCharCode(charCode)
  );

console.log(decodeHtmlCharCodes("’"));

to create the decodeHtmlCharCodes function that calls str.replace with a regex to match all HTML entities with /(&#(\d+);)/g.

And we replace them all with the character that’s returned from String.fromCharCode(charCode).

The charCode in the callback is the character code of the whole HTML entity.

Conclusion

To convert special characters to HTML in JavaScript, we can us the String.fromCharcode method.

Sometimes, we want to create multidimensional array with JavaScript.

In this article, we’ll look at how to create multidimensional array with JavaScript.

How to create multidimensional array with JavaScript?

To create multidimensional array with JavaScript, we can use a for loop.

For instance, we write

let row = 20;
let column = 10;
let f = new Array();

for (i = 0; i < row; i++) {
  f[i] = new Array();
  for (j = 0; j < column; j++) {
    f[i][j] = 0;
  }
}

to create a nested for loop that adds the nested arrays to the f array with the outer loop.

In the inner loop, we fill the nested arrays with 0’s with

for (j = 0; j < column; j++) {
  f[i][j] = 0;
}

Conclusion

To create multidimensional array with JavaScript, we can use a for loop.