本文实例讲述了JS+HTML5FileReader对象用法。分享给大家供大家参考，具体如下：FileReader实例
本文实例讲述了JS+HTML5 FileReader对象用法。分享给大家供大家参考，具体如下：
FileReader 实例中有四个方法来读取文件数据
1、readAsBinaryString(Blob|File)
2、readAsDataURL(Blob|File)
3、readAsText(Blob|File)
4、readAsArrayBuffer(Blob|File)
FileReader 实例包含很多事件（onerror, onprogress, onload[result]）
<input name="file" id="uploadFile" />
var file = document.getElementById("uploadFile");
var bufferSize = 1024;
var pos = 0;
var onload = function(e) {
console.log("Read", e.target.result);
var img = document.createElement("img");
img.src = e.target.result;
img.width = 300;
img.height = 300;
document.body.appendChild(img);
};
var onerror = function() {}
var onprogress = function(e) {}
file.onchange = function() {
if (file.files) file = file.files[0];
while (pos < file.size) {
var reader = new FileReader();
reader.onload = onload;
reader.onerror = onerror;
/*reader.readAsText(file.slice(pos, bufferSize));
pos += bufferSize; */
reader.readAsDataURL(file);
pos = file.size + 1;
}
}