filereader | 易学教程

image,onload event not working in chrome

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问题 I'm using html5 to create drag and drop image upload functionality. This works great for me in firefox but in chrome the image onload event only fires the first time. If I drag multiple images in only the first works and if I drag a second in it fails. I believe the problem is with the image onload. here is the way my code works I have removed the irrelevant sections: var img = document.createElement("img"); var reader = new FileReader(); var canvas = document.createElement("canvas"); var

Java Cannot Read From File

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问题 I am writing a Java program that can take user entries and save them into an ArrayList, then use the ArrayList to open a series of webpages. The program should also be able to read in web addresses from a file. This is where I'm having issues. I'm currently gettting: The file bills.txt was not found. //the file is in my src folder Exception in thread "main" java.lang.NullPointerException at PayBills.main(PayBills.java:92) //this is when the BufferdReader is closed This isn't homework but the

HTML Link parsing using BeautifulSoup

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问题 here is my Python code which I'm using to extract the Specific HTML from the Page links I'm sending as parameter. I'm using BeautifulSoup. This code works fine for sometimes and sometimes it is getting stuck! import urllib from bs4 import BeautifulSoup rawHtml = '' url = r'http://iasexamportal.com/civilservices/tag/voice-notes?page=' for i in range(1, 49): #iterate url and capture content sock = urllib.urlopen(url+ str(i)) html = sock.read() sock.close() rawHtml += html print i Here I'm

Trying to upload multiple images using XHR 2 and PHP

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问题 I'm having problems trying to upload files using the latest XHR 2 along with PHP. My code is as follows: HTML... <!doctype html> <html> <head> <title>XHR Multiple File Upload</title> <link rel="stylesheet" type="text/css" href="upload.css"> </head> <body> <input type="file" id="upload" multiple="true" accept="image/*"> <a href="#" id="upload-link">Click here to upload multiple files</a> <script src="upload.js"></script> </body> </html> JavaScript var formdata, link, input, doc = document; if

Read FileReader object line-by-line without loading the whole file into RAM

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问题 Now that many browsers support reading local files with HTML5's FileReader, this opens the door to websites which go beyond 'database front-ends' into scripts which can do something useful with local data without having to send it up to a server first. Pre-processing images and video before upload aside, one big application of FileReader would be loading data from some kind of on-disk table (CSV, TSV, whatever) into the browser for manipulation - perhaps for plotting or analysis in D3.js or

How to fix exception MethodAccessException during file reading?

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问题 I have to read a text file which added in my project DataMid/Bigram_MidWord.txt where DataMid is a folder and Bigram_MidWord.txt is a file to read. When i write the statement FileStream fileStream = new FileStream(@"/SourceCode,component/DataMid/Bigram_MidWord.txt", FileMode.Open, FileAccess.ReadWrite); then i get the exception as follows: Attempt to access the method failed: System.IO.FileStream..ctor(System.String, System.IO.FileMode, System.IO.FileAccess) How can I fix this issue? 回答1: The

Determining the last file chunk

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问题 I'm trying to setup a file upload through rest for large files. The function below is taking care of chunking but I need to be able to recognize the last chunk because my rest call changes to /finishUpload() in order to commit the save. Right now I'm only able to figure out when the blob is empty but I can't figure out how to determine the last iteration before the blob is empty. This is the script I'm using below to parse my files. export default function parseFile(file, options) { var opts

Convert Image to Binary Data or String in Javascript

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问题 I am working on uploading image file to TWITPIC using XMLHttp Request on a Chrome Extension . I need to send the image as payload. Is there a way to do this ? I found this link Convert an image into binary data in javascript But that works on image tags. i need a way to specify image file path and upload image to TWITPIC. I came to know about FileReader API with HTML 5. Is there any way to work using that??. It should work on a local file. Does Chrome Extension support FileReader API without

JS 图片转Base64

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JS 图片转Base64 有时候需要向HTML中插入一张图片，可苦于上线后找不到一个合适的网盘来存储这些图片，有没有一种办法能将图片转换成文字，然后直接插入HTML中呢，通过 Base64 编码就可以解决这个问题。废话不多说直接上代码。不知道什么是 Base64 的请自行百度。 JS 图片转Base64 图片转Base64 示例代码 <!DOCTYPE html > <html> <head> <meta charset = "UTF-8" > <title> JS 图片转Base64 </title> <script src = "//cdn.bootcss.com/jquery/2.2.0/jquery.min.js" ></script> <script> function run ( input_file , get_data ){ /*input_file：文件按钮对象*/ /*get_data: 转换成功后执行的方法*/ if ( typeof ( FileReader ) === 'undefined' ){ alert ( "抱歉，你的浏览器不支持 FileReader，不能将图片转换为Base64，请使用现代浏览器操作！" ); } else { try { /*图片转Base64 核心代码*/ var file = input_file . files [

Setting backgroundImage style from a FileReader

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问题 I am looking for a solution that allows me to take a file from a file upload input and preview it by setting the document.body.style.backgroundImage. The following code works to display a preview in an Image element: function setImage(id, target){ input = document.getElementById(id); if (input.files && input.files[0]) { var reader = new FileReader(); reader.onload = function (e) { target.src = e.target.result; }; reader.readAsDataURL(input.files[0]); } } Where id is the id of the <input type=