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:157Please respect copyright.ＰＥＮＡＮＡOMx1TW6Ruq
---read whole file content into array buffer---157Please respect copyright.ＰＥＮＡＮＡluSbzaJHXS
let file=input.files[0]; const reader = new FileReader(); 157Please respect copyright.ＰＥＮＡＮＡsPp7yKgnEn
reader.onload = () => 157Please respect copyright.ＰＥＮＡＮＡX6MGitCnqh
{157Please respect copyright.ＰＥＮＡＮＡPUoSFHqChq
let content_whole = new Uint8Array(reader.result);157Please respect copyright.ＰＥＮＡＮＡJhC5Q9uD1l
}157Please respect copyright.ＰＥＮＡＮＡUly1fZTct9
reader.readAsArrayBuffer(file);157Please respect copyright.ＰＥＮＡＮＡ8B7s07zmKy
-----------------------------------------------
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:157Please respect copyright.ＰＥＮＡＮＡ04UX6lTwpW
---read part of file content into array buffer---157Please respect copyright.ＰＥＮＡＮＡD16oP0ChxI
let file=input.files[0], block_size=1000000, start=0, end=block_size; const reader = new FileReader(); 157Please respect copyright.ＰＥＮＡＮＡ5irZRjyP2r
reader.onload = () => 157Please respect copyright.ＰＥＮＡＮＡEWLWbyaWep
{157Please respect copyright.ＰＥＮＡＮＡZ98jBbFdAe
let content_part = new Uint8Array(reader.result);157Please respect copyright.ＰＥＮＡＮＡYtjmaWXpWs
}157Please respect copyright.ＰＥＮＡＮＡ8Gl6kRLOzF
reader.readAsArrayBuffer(file.slice(start,end));157Please respect copyright.ＰＥＮＡＮＡJmat02GyZg
-----------------------------------------------
157Please respect copyright.ＰＥＮＡＮＡFpYNrIDVPg
Section X. Thanks157Please respect copyright.ＰＥＮＡＮＡ6lxbZf9FHF
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]157Please respect copyright.ＰＥＮＡＮＡ6wcy3khvm4
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。
ns216.73.216.160da2
