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:76Please respect copyright.ＰＥＮＡＮＡTlVlxfWlro
---read whole file content into array buffer---76Please respect copyright.ＰＥＮＡＮＡ6gTb3Xhysy
let file=input.files[0]; const reader = new FileReader(); 76Please respect copyright.ＰＥＮＡＮＡkAAmhngwEr
reader.onload = () => 76Please respect copyright.ＰＥＮＡＮＡEnntGxft9p
{76Please respect copyright.ＰＥＮＡＮＡk1K50DPcrD
let content_whole = new Uint8Array(reader.result);76Please respect copyright.ＰＥＮＡＮＡs5FrlmzaIM
}76Please respect copyright.ＰＥＮＡＮＡEYlQNhZeIa
reader.readAsArrayBuffer(file);76Please respect copyright.ＰＥＮＡＮＡmBXkFtZ0r3
-----------------------------------------------
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:76Please respect copyright.ＰＥＮＡＮＡn2OjflDRGh
---read part of file content into array buffer---76Please respect copyright.ＰＥＮＡＮＡj0kSxePUve
let file=input.files[0], block_size=1000000, start=0, end=block_size; const reader = new FileReader(); 76Please respect copyright.ＰＥＮＡＮＡCwcrOTof80
reader.onload = () => 76Please respect copyright.ＰＥＮＡＮＡ9XsKlZCqyM
{76Please respect copyright.ＰＥＮＡＮＡaUTaN0myqL
let content_part = new Uint8Array(reader.result);76Please respect copyright.ＰＥＮＡＮＡlmnkr53Jt5
}76Please respect copyright.ＰＥＮＡＮＡL3kzvPeTQV
reader.readAsArrayBuffer(file.slice(start,end));76Please respect copyright.ＰＥＮＡＮＡCEuQIlXjwj
-----------------------------------------------
76Please respect copyright.ＰＥＮＡＮＡWfNT4Agf4x
Section X. Thanks76Please respect copyright.ＰＥＮＡＮＡtcCp8zGZVS
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: si.jinmin@gmail.com76Please respect copyright.ＰＥＮＡＮＡYMCynwAhDG
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: si.jinmin@gmail.com
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。
ns18.219.128.212da2
