The following simple function allow you to generate a download of a file directly in the browser without contact any server. Here, the property has been set to the path of the file that is to be downloaded by the clients machine. In this article we are going to show you a couple of tricks to generate and download directly a file using pure Javascript. Therefore, the automatic download of file has been difficult to achieve in the latest years, but now with the introduction of HTML5, this task has become easier to achieve. However, in the latest browsers unknow or rare downloaded file extensions are blocked and a prompt appears if you really want to open that file (at less in Chrome). This is particularly useful for situations when you want to create large. Thus, Blobs can be used to temporarily store large amounts of data without running out of memory.

According to Google's guide on chrome's blob implementation, Blob data is paginated to disk when memory is scarce. Imagine that you use Google Chrome and you have enabled the option 'Auto-open downloaded files', and for your bad luck you enter in a malicious website and it generates the download of an unknown file. Making large download files client-side in Incognito mode.

Generate and download a file using Javascript ? If you think about it, this isn't so secure as you think and shouldn't be allowed without the user interaction (however now is allowed).

Javascript download file to client