---
title: File.size
slug: Web/API/Blob/size
translation_of: Web/API/Blob/size
---
<h3 id="概述">概述</h3>
<p>返回一个File对象所指代的文件的大小，单位为字节。</p>
<h3 id="例子">例子</h3>
<pre class="brush:js">// fileInput是一个HTMLInputElement元素: &lt;input type="file" multiple id="myfileinput"&gt;
var fileInput = document.getElementById("myfileinput");
// files是一个FileList对象(类似于NodeList)
var files = fileInput.files;
for (var i = 0; i &lt; files.length; i++)
{
    alert(files[i].name + "文件的大小为 " + files[i].size + " 字节");
}
</pre>
<p>{{ languages( {"en": "en/DOM/File.size" } ) }}</p>