js异步上传图片
<!DOCTYPE html>
<html xmlns = "http://www.w3.org/1999/xhtml" >
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8" />
<title> </title>
<script type="text/javascript" src="jquery.js"></script>
<script type = "text/javascript" >
function ProcessFile( e ) {
var e= e||event;
var file = document.getElementById('file').files[0];
if ( file ) {
var reader = new FileReader();
reader.onload = function ( event ) {
var txt = event.target.result;
var img = document.createElement("img");
img.src = txt;
img.style.cssText="width:100px;height:100px;border:1px solid red;"
document.getElementById("result").appendChild( img );
};
}
reader.readAsDataURL( file );
}
function contentLoaded() {
document.getElementById('file').addEventListener( 'change' ,
ProcessFile , false );
}
window.addEventListener( "DOMContentLoaded" , contentLoaded , false );
window.onload = function(){
var oBtn = document.getElementById('btn1');
oBtn.onclick = function(){
var fd = new FormData();
var file =document.getElementById("file").files[0];
console.log(file)
fd.append('file',file);
$.ajax({
type:"post",
url:'a.php',
processData: false,
contentType: false,
data:fd,
success:function(data)
{
}
})
}
}
</script>
</head>
<body>
请选择一个图片: <input type = "file" id = "file" name = "file" />
<div id = "result"> </div>
<br>
<button id="btn1">上传 </button>
</body>
</html>
平时做表单都是跳转提交的，但是今天要做一个ajax图片异步上传，
网上搜索了下，方法都比较老了，居然还有用flash的，
普通的表单上传通过jquery的serialize()转换成querystring后就可以直接ajax post 上传，但是碰到文件上传就不奏效了，型号html5有个方法FormData()可以实现上传，
我写的代码如下：
function upThumbSubmit() {
if(!window.FormData) {
alert('your brower is too old');
return false;
}
var formData = new FormData($( "#upForm" )[0]);
$.ajax({
url:'?c=api&a=upload',
type:'post',
data:formData,
dataType:'json',
success:function(data){
alert(data);
return false;
}
});
}
但是报错了，错误如下
TypeError: 'append' called on an object that does not implement interface FormData.
既然浏览器明明显示支持formdata,为何这里显示append不是formdata接口呢？
答案只可能是jquery重载了formdata
在里面加上2个option,就好了，正确代码如下
function upThumbSubmit() {
if(!window.FormData) {
alert('your brower is too old');
return false;
}
var formData = new FormData($( "#upForm" )[0]);
$.ajax({
url:'?c=api&a=upload',
type:'post',
data:formData,
processData: false,
contentType: false,
dataType:'json',
success:function(data){
alert(data);
return false;
}
});
}
