HTML5 Ajax 2.0标准中，增强了Ajax的许多功能，包括发送FormData数据，上传数据进度条等诸多功能。但实际上，Ajax可以字节发送二进制数据。
发送二进制数据
var oReq = new XMLHttpRequest();
oReq.open("POST",url,true);
oReq.onload = function (oEvent) {
// Uploaded.
};
var blob = new Blob(['abc123'],{type: 'text/plain'});
oReq.send(blob);
或者
var myArray = new ArrayBuffer(512);
var longInt8View = new Uint8Array(myArray);
for (var i=0; i< longInt8View.length; i++) {
longInt8View[i] = i % 255;
}
var xhr = new XMLHttpRequest;
xhr.open("POST",false);
xhr.send(myArray);
接收二进制数据
var oReq = new XMLHttpRequest();
oReq.open("GET","/myfile.png",true);
oReq.responseType = "arraybuffer";
oReq.onload = function (oEvent) {
var arrayBuffer = oReq.response; // Note: not oReq.responseText
if (arrayBuffer) {
var byteArray = new Uint8Array(arrayBuffer);
for (var i = 0; i < byteArray.byteLength; i++) {
}
}
};
oReq.send(null);
当然，如上设置只能是文本类型，如果是Blob类型，那么如下即可
var oReq = new XMLHttpRequest();
oReq.open("GET",true);
oReq.responseType = "arraybuffer";
oReq.onload = function(oEvent) {
var blob = new Blob([oReq.response],{type: "image/png"});
// ...
};
oReq.send();
或者
var oReq = new XMLHttpRequest();
oReq.open("GET",true);
oReq.responseType = "blob";
oReq.onload = function(oEvent) {
var blob = oReq.response;
// ...
};
oReq.send();
如果你使用的是旧版本的浏览器，那么加载二进制可以如下
function load_binary_resource(url) {
var req = new XMLHttpRequest();
req.open('GET',false);
//XHR binary charset opt by marcus Granado 2006 [http://mgran.blogspot.com]
req.overrideMimeType('text\/plain; charset=x-user-defined');
req.send(null);
if (req.status != 200) return '';
return req.responseText;
}
注意:x-user-defined告诉浏览器不要解析数据
参考：
http://www.tuicool.com/articles/iiui7ff
https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Sending_and_Receiving_Binary_Data