This will help us to replace certain special characters with a combination of escape sequences. Append this created element to the body of the document HTML page. Use element. Remove the element from the body of the document HTML page. Attach this link to the document and simulate a click using the.
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The idea is to programmatically create an anchor link, and then trigger the click event. This method is especially helpful for dynamically generated file URLs. Sometimes, you may want to save programmatically generated data as a file using JavaScript. That's where blobs and object URLs are useful.
A Blob object is a file-like object used to represent raw immutable data. Blob objects contain information about the type and size of data they store, making them very useful for storing dynamic contents in the browser. This method is helpful to create an object URL that represents a blob or a file. The browser will release all object URLs when the document is closed or reloaded.
However, it is a good practice to release object URLs whenever they are no longer required to improve performance and minimize memory usage.
Notice in the GIF above that once we click the Download button, nothing seems to happen, because the download takes place as an asynchronous task in our application and once it is completed, it will be passed to the browser. Once that browser window appears and we click save, the file is automatically saved on our computer. With this method now we are able to download any type of file regardless of the origin server.
However, the problem is that because the download takes place inside our application, the user may think that nothing happened when he clicked and therefore it is up to us to manage large file downloads by implementing the measurement of progress. At the same time, this method is useful when we need to perform certain actions inside our application once the file has completed downloaded.
Show a message, send a request to the back-end render a new page, and so on…. The beginning and the onreadystatechange block is similar to the second function. Download the response as a Blob object, create a DOMString, and use an anchor element to download the file.
Inside onprogress we use e. Notice in the GIF above that we have the same behavior as for the second method, only now we can monitor progress. After the file is completely downloaded, it will be sent to the browser and then it will be instantly saved to disk. Each of the above methods represents an update over the previous method.
The first method is the easiest. In this, we simply forward the download process to the browser to manage it natively. This method is the preferred way when the application does not have to perform certain actions based on the load state.
In the second, we manage the download internally and send it to the browser only when the download is complete. In this way, we can control the download inside the application and we can react depending on its status. This method works well for small files that are downloaded quickly, but when the file is too large, the user may think that the application is faulty, if nothing happens on the UI to indicate to the user that a download is in progress.
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