js操作一般文件和csv文件
-
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);
}
}) -
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;
}
}) -
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);
}