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:116Please respect copyright.ＰＥＮＡＮＡvMGl2XF25c
---read whole file content into array buffer---116Please respect copyright.ＰＥＮＡＮＡOCVA8qAX3S
let file=input.files[0]; const reader = new FileReader(); 116Please respect copyright.ＰＥＮＡＮＡ3b7sYqVdKo
reader.onload = () => 116Please respect copyright.ＰＥＮＡＮＡ7eRLbWmBLs
{116Please respect copyright.ＰＥＮＡＮＡ6tTTZd629A
let content_whole = new Uint8Array(reader.result);116Please respect copyright.ＰＥＮＡＮＡvZ2hdvIFuM
}116Please respect copyright.ＰＥＮＡＮＡvEjhDsyNWQ
reader.readAsArrayBuffer(file);116Please respect copyright.ＰＥＮＡＮＡzysKd3ScCu
-----------------------------------------------
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:116Please respect copyright.ＰＥＮＡＮＡS7obkIOn8z
---read part of file content into array buffer---116Please respect copyright.ＰＥＮＡＮＡnzYBixgXl1
let file=input.files[0], block_size=1000000, start=0, end=block_size; const reader = new FileReader(); 116Please respect copyright.ＰＥＮＡＮＡ1kNuCr7bhS
reader.onload = () => 116Please respect copyright.ＰＥＮＡＮＡCYKwK4Zt7l
{116Please respect copyright.ＰＥＮＡＮＡxzLODN7nx3
let content_part = new Uint8Array(reader.result);116Please respect copyright.ＰＥＮＡＮＡeUccoU39F7
}116Please respect copyright.ＰＥＮＡＮＡeDsL9Vyks1
reader.readAsArrayBuffer(file.slice(start,end));116Please respect copyright.ＰＥＮＡＮＡF7WuQN0B0c
-----------------------------------------------
116Please respect copyright.ＰＥＮＡＮＡZTtCJAe3VK
Section X. Thanks116Please respect copyright.ＰＥＮＡＮＡ8mdzzbQT34
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]116Please respect copyright.ＰＥＮＡＮＡc4khTtkWuV
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。
ns216.73.216.122da2
