image标签src的格式有时候会是base64如下：
<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAkCAYAAABIdFAMAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAHhJREFUeNo8zjsOxCAMBFB/ KEAUFFR0Cbng3nQPw68ArZdAlOZppPFIBhH5EAB8b+Tlt9MYQ6i1BuqFaq1CKSVcxZ2Acs6406KUgpt5/ LCKuVgz5BDCSb13ZO99ZOdcZGvt4mJjzMVKqcha68iIePB86GAiOv8CDADlIUQBs7MD3wAAAABJRU5ErkJggg==">
首先需要 吧 base64 流转换成 blob 对象，文件对象都继承它。
function getBlobBydataURI(dataURI,type) {
var binary = atob(dataURI.split(',')[1]);
var array = [];
for(var i = 0; i < binary.length; i++) {
array.push(binary.charCodeAt(i));
}
return new Blob([new Uint8Array(array)], {type:type });
}
剩下的就作为文件上传了
let $Blob = new Blob([new Uint8Array(array)], {type:'image/jpeg' });
let formData = new FormData();
formData.append("files", $Blob ,"file_"+ Date.parse(new Date()) + ".jpg");
完整代码：
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title>上传用例</title>
<meta content='width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no' name='viewport'>
<script type="text/javascript">
/**
* 根据base64 内容 取得 bolb
*
* @param dataURI
* @returns Blob
*/
function getBlobBydataURI(dataURI,type) {
var binary = atob(dataURI.split(',')[1]);
var array = [];
for(var i = 0; i < binary.length; i++) {
array.push(binary.charCodeAt(i));
}
return new Blob([new Uint8Array(array)], {type:type });
}
/**
* 上传
*/
function upload(){
//base64 转 blob
var $Blob= getBlobBydataURI(document.getElementsByTagName("img")[0].currentSrc,'image/jpeg');
var formData = new FormData();
formData.append("files", $Blob ,"file_"+Date.parse(new Date())+".jpeg");
//组建XMLHttpRequest 上传文件
var request = new XMLHttpRequest();
//上传连接地址
request.open("POST", "www.xxx.com");
request.onreadystatechange=function()
{
if (request.readyState==4)
{
if(request.status==200){
console.log("上传成功");
}else{
console.log("上传失败,检查上传地址是否正确");
}
}
}
request.send(formData);
}
</script>
</head>
<body>
<button onclick="upload()">上传测试</button>
<br />
上传的图片:
<img src="data:image/jpeg;base64,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" />
</body>
</html>