本文描述了使用javascript读取用户通过Input控件选择的文件的内容的方法和注意事项。后面用英文写，但我的英文不太好，如有错误之处，希望大家帮我纠正，我的联系方式在后面。
When user select a file by <input type=file>, its content can be read by javascript like this:52Please respect copyright.ＰＥＮＡＮＡWRkbU67m2z
---read whole file content into array buffer---52Please respect copyright.ＰＥＮＡＮＡUMrqEd3dKU
let file=input.files[0]; const reader = new FileReader(); 52Please respect copyright.ＰＥＮＡＮＡIXPg27wXeO
reader.onload = () => 52Please respect copyright.ＰＥＮＡＮＡ3Ui6KOlvgF
{52Please respect copyright.ＰＥＮＡＮＡ4YJSxAkTfI
let content_whole = new Uint8Array(reader.result);52Please respect copyright.ＰＥＮＡＮＡSvwGO4HRW3
}52Please respect copyright.ＰＥＮＡＮＡteviW5ppsg
reader.readAsArrayBuffer(file);52Please respect copyright.ＰＥＮＡＮＡBM30E2P3Ym
-----------------------------------------------
If the file size is too large, the browser may crash as the whole file content are loaded into memory by array buffer. In order to avoid it, we can just read a part of the file like this:52Please respect copyright.ＰＥＮＡＮＡmArzC44t90
---read part of file content into array buffer---52Please respect copyright.ＰＥＮＡＮＡyocfnkl8Pa
let file=input.files[0], block_size=1000000, start=0, end=block_size; const reader = new FileReader(); 52Please respect copyright.ＰＥＮＡＮＡMmtXgyQQBu
reader.onload = () => 52Please respect copyright.ＰＥＮＡＮＡzwSnmipEtO
{52Please respect copyright.ＰＥＮＡＮＡgLaRSSGLVg
let content_part = new Uint8Array(reader.result);52Please respect copyright.ＰＥＮＡＮＡTP0l00Ghm3
}52Please respect copyright.ＰＥＮＡＮＡAoQW5jU9E4
reader.readAsArrayBuffer(file.slice(start,end));52Please respect copyright.ＰＥＮＡＮＡ6ycM8SUIYH
-----------------------------------------------
52Please respect copyright.ＰＥＮＡＮＡqTmOW0CH4V
Section X. Thanks52Please respect copyright.ＰＥＮＡＮＡrcKW89Wp8P
https://segmentfault.com/a/1190000022113605
Section Y. Contacts Me
If you found any errors or have any suggestions for this article, please let me know, my wechat: si_jinmin, my email: [email protected]52Please respect copyright.ＰＥＮＡＮＡ2eeAEMRj3k
如果您发现本文有任何错误，或者对本文有好的建议，欢迎与我联系探讨，我的微信: si_jinmin, 我的email: [email protected]
如果您對C/C++ Programming, Linux, HTTP Protocol, Website Development, Vue, Git, VsCode感興趣，邀請您加入「Linux/C/C++ Website Development」微信群，請加我的微信（si_jinmin）以便拉您进群。
ns3.144.113.235da2
然後按「加至主畫面」