Category: JavaScript Answers

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JavaScript Answers

How to check if DOM is ready without a framework with JavaScript?

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Sometimes, we want to check if DOM is ready without a framework with JavaScript.

In this article, we’ll look at how to check if DOM is ready without a framework with JavaScript.

How to check if DOM is ready without a framework with JavaScript?

To check if DOM is ready without a framework with JavaScript, we can listen for the DOMContentLoaded event.

For instance, we write

document.addEventListener("DOMContentLoaded", (event) => {
  console.log("DOM fully loaded and parsed");
});

to listen for the DOMContentLoaded event with addEventListener.

We call it with a callback that runs when the DOM is fully loaded.

Conclusion

To check if DOM is ready without a framework with JavaScript, we can listen for the DOMContentLoaded event.

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JavaScript Answers

How to dynamically create HTML5 canvas with JavaScript?

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Sometimes, we want to dynamically create HTML5 canvas with JavaScript.

In this article, we’ll look at how to dynamically create HTML5 canvas with JavaScript.

How to dynamically create HTML5 canvas with JavaScript?

To dynamically create HTML5 canvas with JavaScript, we can use the createElement method.

For instance, we write

const canvas = document.createElement("canvas");
canvas.id = "canvas";
canvas.width = 1224;
canvas.height = 768;
canvas.style.zIndex = 8;
canvas.style.position = "absolute";
canvas.style.border = "1px solid";

to create the canvas element with createElement.

Then we set its id, width, height, zIndex, position, and border. to set its size, position, border and ID.

Conclusion

To dynamically create HTML5 canvas with JavaScript, we can use the createElement method.

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JavaScript Answers

How to get width in pixels from element with style set with % with JavaScript?

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Sometimes, we want to get width in pixels from element with style set with % with JavaScript.

In this article, we’ll look at how to get width in pixels from element with style set with % with JavaScript.

How to get width in pixels from element with style set with % with JavaScript?

To get width in pixels from element with style set with % with JavaScript, we can use the offsetWidth property.

For instance, we write

document.querySelector("div").offsetWidth;

to select the div with querySelector.

Then we get the width of the element with offsetWidth in pixels.

Conclusion

To get width in pixels from element with style set with % with JavaScript, we can use the offsetWidth property.

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JavaScript Answers

How to call a JavaScript function at a specific time of day?

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Sometimes, we want to call a JavaScript function at a specific time of day.

In this article, we’ll look at how to call a JavaScript function at a specific time of day.

How to call a JavaScript function at a specific time of day?

To call a JavaScript function at a specific time of day, we call setTimeout with the number of milliseconds between now and the date and time we want to call the function.

For instance, we write

const etaMs = new Date(2023, 0, 21, 17, 0).getTime() - Date.now();
const timeout = setTimeout(() => {}, etaMs);

to call setTimeout with the function we want to run after etaMs milliseconds has elapsed.

We subtract the timestamp of the future date time by the timestamp of the current timestamp to get the number of milliseconds to wait before we call the setTimeout callback.

Conclusion

To call a JavaScript function at a specific time of day, we call setTimeout with the number of milliseconds between now and the date and time we want to call the function.

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JavaScript Answers

How to parse ISO 8601 date in JavaScript?

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Sometimes, we want to parse ISO 8601 date in JavaScript.

In this article, we’ll look at how to parse ISO 8601 date in JavaScript.

How to parse ISO 8601 date in JavaScript?

To parse ISO 8601 date in JavaScript, we can use the Date constructor.

For instance, we write

const d = new Date("2022-04-07T13:58:10.104Z");
console.log(d.toString());

to create a Date object with an ISO 8601 date time string.

Then we use toString to return the string version of the date.

Conclusion

To parse ISO 8601 date in JavaScript, we can use the Date constructor.