Section 1.1: Listening for the Load Event

To check if a background image has loaded, we can listen for the load event associated with the image. When the image is fully loaded, we can then apply it as the background image.

For example, consider the following code snippet:

const bgElement = document.querySelector("body");

let preloaderImg = document.createElement("img");

preloaderImg.src = imageUrl;

preloaderImg.addEventListener('load', (event) => {

bgElement.style.backgroundImage = url(${imageUrl});

preloaderImg = null;

});

In this example, we define the imageUrl variable with the URL of the image we want to use as the background. We use document.querySelector to select the body element, and then create an img element to preload the specified image.

We set the src attribute of the preloaderImg to our imageUrl. By adding an event listener for the 'load' event on preloaderImg, we ensure that the callback function executes once the image has fully loaded.

Once it has loaded, we set the bgElement.style.backgroundImage to the loaded image. Finally, we set preloaderImg to null, effectively clearing the reference to the preloaded image.

Now, you should see the background image displayed on your webpage.

Section 1.2: Conclusion

In summary, by listening for the load event of an image element, we can determine when an image has been successfully loaded. Once the image is ready, we can utilize its URL to set it as the background image of our page.

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