js操作一般文件和csv文件

js操作一般文件和csv文件

1. 将文本文件读成字符串

   <input type="file" id="upload">document.getElementById("upload").addEventListener("change", function() { ???var files = this.files; ???if(files.length == 0) { ???????console.log("没有文件"); ???????return; ???} ???var reader = new FileReader(); ???reader.readAsText(files[0]); ???reader.onload = function(e) { ???????console.log("文件内容如下\n"+e.target.result); ???}})

2. 将读取的图片展示在页面上

   <input type="file" id="upload" accept="image/png">document.getElementById("upload").addEventListener("change", function() { ???var files = this.files; ???if(files.length == 0) { ???????console.log("没有文件"); ???????return; ???} ???var reader = new FileReader(); ???reader.readAsDataURL(files[0]); ???reader.onload = function(e) { ???????var img = new Image(); ???????img.style.width = "200px"; ???????img.style.height = "100px" ???????img.onload = function() { ???????????document.body.appendChild(img); ???????} ???????img.src = e.target.result; ???}})

3. 处理和下载csv文件

   var blob = new Blob([ ???`Year,Make,Model,Description,Price ???1997,Ford,E350,"ac, abs, moon",3000.00 ???1999,Chevy,"Venture ""Extended Edition""","",4900.00 ???1999,Chevy,"Venture ""Extended Edition, Very Large""",,5000.00 ???1996,Jeep,Grand Cherokee,"MUST SELL! ???air, moon roof, loaded",4799.00`]) ???????if(window.navigator.msSaveOrOpenBlob){ ???window.navigator.msSaveBlob(blob, "test.csv");}else { ???var a = window.document.createElement("a"); ???a.href = window.URL.createObjectURL(blob, { ???????type: "text/plain" ???}); ???a.download = "test.csv"; ???document.body.appendChild(a); ???a.click(); ???document.body.removeChild(a);} ???

js操作一般文件和csv文件

原文地址：https://www.cnblogs.com/ye-hcj/p/10353974.html