Trigger a Browser's Save-As Dialog via Javascript using only On-page data

As part of my page's output, I'm including a CSV formatted version of a d开发者_C百科ata table in a text area, so that the user can easily copy/paste a CSV export into their spreadsheet of choice.

I would like a way to have a button that, when clicked, will trigger a Save-as dialog that will download the CSV contents already present in the textarea on the page.

The intention is to avoid another trip to the database to get the CSV export, when it is already on the page, while providing the user a shortcut around having to create a new file and paste in the copied CSV.

Is this possible?

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I don't think it's currently possible to trigger save as without doing some sort of request back to the server, but it's possible to export data from a loaded page using a Data URI. Have a look at my answer to this similar question.