<html>
<head>
<title></title>
<meta charset="UTF-8" />
<script src="jquery-3.1.1.min.js" type="text/javascript" charset="utf-8"></script>
</head>
<body>
<form name="form1" id="form1" enctype="multipart/form-data">
<input type="file" name="img" id="img" value="" onchange="dj()" />
</form>
<script type="text/javascript">
function dj() {
var form = document.getElementById(‘form1‘);
var oMyForm = new FormData();
oMyForm.append("username", "Groucho");
oMyForm.append("sex", "Groucho");
oMyForm.append(‘img‘, $(‘#img‘)[0].files[0]);
$.ajax({
url: "http://192.168.1.105/ifangApi/?s=Api/Order/aa",
type: "POST",
data: oMyForm,
processData: false, // 告诉jQuery不要去处理发送的数据
contentType: false // 告诉jQuery不要去设置Content-Type请求头
});
}
</script>
</body>
</html>
原文：http://www.cnblogs.com/nns4/p/7514750.html