How to reliably trigger an alert box when an image is loaded, even if it\'s cached?

Handling Image Load Events with Browser Cache Considerations

In web development, it is essential to manage image loading events effectively, especially when images may be cached by the browser. One challenge arises when attempting to trigger an alert box when an image is loaded, as the ".onload" event may not fire if the image is retrieved from the cache.

To overcome this issue, it is crucial to set the ".onload" property before assigning the source URL ("src") to the image object. This ensures that the event listener is defined before the image starts loading. Here's a modified code snippet that addresses this:

var img = new Image();
img.onload = function () {
   alert("image is loaded");
}
img.src = "img.jpg";

Moreover, some browsers might also require the image to be loaded before the ".onload" property can be set, in which case a workaround using jQuery or a polyfill can be used:

$(img).on('load', function() {
  alert("image is loaded");
});
img.src = "img.jpg";

By implementing these techniques, you can ensure that an alert box will be triggered whenever an image is loaded, regardless of whether it is fetched from the cache or downloaded from the server. This approach optimizes user experience by providing timely feedback on image loading progress.

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