<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>upload</title>
</head>
<body>
<input accept="image/*" name="upimage" id="upload_file" type="file">
<textarea id="base64_output" name="Word" style=" width:820px"></textarea>
<script type="text/javascript">
document.getElementById("upload_file").onchange = function () {
gen_base64();
};
function $_(id) {
return document.getElementById(id);
}
function gen_base64() {
var file = $_(‘upload_file‘).files[0];
r = new FileReader(); //本地预览
r.onload = function(){
$_(‘base64_output‘).value = r.result;
}
r.readAsDataURL(file); //Base64
}
</script>
</body>
</html>
摘自：https://www.cnblogs.com/Strom-HYL/p/6782176.html
