Blob: size property
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
Note: This feature is available in Web Workers.
The size read-only property of the Blob interface returns
the size of the Blob or File in bytes.
Value
The number of bytes of data contained within the Blob (or
Blob-based object, such as a File).
Examples
This example uses an <input> element of type file to ask
the user for a group of files, then iterates over those files outputting their names and
lengths in bytes.
HTML
html
<input type="file" id="input" multiple />
<output id="output">Choose files…</output>
JavaScript
js
const input = document.getElementById("input");
const output = document.getElementById("output");
input.addEventListener("change", (event) => {
output.innerText = "";
for (const file of event.target.files) {
output.innerText += `${file.name} has a size of ${file.size} bytes.\n`;
}
});
Result
Specifications
| Specification |
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| File API # dfn-size |
Browser compatibility
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
- Has more compatibility info.