kept in the document memory space until the document is unloaded or the CAUTION: At this point, the URL has been allocated and the blob will be Create an addressable version of the blob. particular demo), we need to be sure to release the previous Object URL going to create a new URL every time the user hits a key-stroke (in this document is unloaded or until the URL is explicitly released. When we create Object URLs, the browser will keep them in memory until the Create a binary representation of the plain-text input. I update the HREF of the download link to point to the textarea payload. Input.addEventListener( "input", updateDownloadHref, false ) attribute of our download link to contain the proper Object URL. Listen for relevant form changes so that we can dynamically update the HREF We'll need to keep track of those so we can manage the browser memory. In order to facilitate the download, we're going to allocate Object URLs. Var download = document.querySelector( "a" ) Var input = document.querySelector( "textarea" ) Luckily, creating a Blob from a plain-text value is as simple as calling the Blob constructor and passing in the text value:ĭownloading Text Using Blobs, URL.createObjectURL(), And The Anchor Download Attribute In JavaScript Of course, in order to use the URL.createObjectURL() method, we need to have a Blob. But, if you're generating a lot of these URLs, you can control the memory consumption more granularly by removing old Blob URIs with the URL.revokeObjectURL(blogURI) method. Depending on what your application is doing, this may or may not be a concern.
When you create a Blob URI, the browser holds onto the referenced memory until the document is unloaded or, until you explicitly revoke the URL.
This method takes a Blob (or Blob-like object) and returns a String that can be used in any place that a URL might be used (such as an HREF attribute). This reference will be generated by the URL.createObjectURL() method. Except, instead of a Data URI, we're going to point the "href" attribute to an in-memory object reference. In this demo, we're going to be using a similar approach. Href="**data:**text/plain charset=utf-8." In the previous demo, I was setting an anchor tag's "href" attribute to point to a Data URI in the form of: View this code in my JavaScript Demos project on GitHub. Run this demo in my JavaScript Demos project on GitHub.
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