利用 HTML 5 的多图片上传及预览（不含前端的文件分割）
主要运用
1、HTML5 files可以选择多文件，以及获取多文件信息
2、XMLHTTPRequest对象，发送HTTP传输请求
3、将每一个文件放在FormData，进行传输
4、利用readAsDataURL将图片内容直接变成url，放在img标签的src当中，生成可预览的图片
html+css+js代码
<!DOCTYPE html>
<head>
<meta http-equiv="Content-Type" content="text/html" charset="utf-8" />
<title>test html FileReader</title>
<style type="text/css">
html,body,header,footer,div,ul,li,h1,h2,h3,h4,h5,h6,label,input,textarea,p,span,a{
padding: 0;
margin: 0;
}
img {
border: 0;
}
em,strong{
font-weight: normal;
font-style: normal;
}
ul {
list-style: none;
}
h1,h2,h3,h4,h5,h6 {
font-weight: normal;
font-size: 100%;
}
a,a:after{
text-decoration:none;
}
.photo_wrap{
clear:both;
}
.photo_wrap li{
margin:10px;
width:150px;
float:left;
}
.photo_box {
height:150px;
width:150px;
overflow:hidden;
position:relative;
}
.photo_box .img1{
height:150px;
}
.photo_box .img2{
width:150px;
}
.upload_result{
height:50px;
}
.btns{
position:relative;
height:40px;
width:100px;
float:left;
}
.btn{
height:40px;
line-height:40px;
color:#FFF;
display:block;
border-radius:3px;
text-align:center;
background-color: #FF5581; /* Old browsers */
background-image: -moz-linear-gradient(top,#FA7B9C 0%, #FF5581 100%); /* FF3.6+ */
background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#FA7B9C), color-stop(100%,#FF5581)); /* Chrome,Safari4+ */
background-image: -webkit-linear-gradient(top,#FA7B9C 0%, #FF5581 100%); /* Chrome10+,Safari5.1+ */
background-image: -o-linear-gradient(top,#FA7B9C 0%, #FF5581 100%); /* Opera 11.10+ */
background-image: -ms-linear-gradient(top,#FA7B9C 0%, #FF5581 100%); /* IE10+ */
background-image: linear-gradient(to bottom,#FA7B9C 0%, #FF5581 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#FA7B9C', endColorstr='#FF5581',GradientType=0 ); /* IE6-8 */
box-shadow:0 1px 0 rgba(255, 255, 255, 0.3) inset, 0 1px 2px rgba(0, 0, 0, 0.3);
}
.btn_add_pic{
width:100px;
position:absolute;
top:0;
left:0;
}
.btn_upload{
width:100px;
margin:0 10px 10px;
float:left;
}
.btn:hover,
.btn_cur{
background-color: #FB99B1; /* Old browsers */
background-image: -moz-linear-gradient(top,#FB99B1 0%, #FF5581 100%); /* FF3.6+ */
background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#FB99B1), color-stop(100%,##FF5581)); /* Chrome,Safari4+ */
background-image: -webkit-linear-gradient(top,#FB99B1 0%, #FF5581 100%); /* Chrome10+,Safari5.1+ */
background-image: -o-linear-gradient(top,#FB99B1 0%, #FF5581 100%); /* Opera 11.10+ */
background-image: -ms-linear-gradient(top,#FB99B1 0%, #FF5581 100%); /* IE10+ */
background-image: linear-gradient(to bottom,#FB99B1 0%, #FF5581 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#FB99B1', endColorstr='#FF5581',GradientType=0 ); /* IE6-8 */
}
.file_input_wrap{
position:absolute;
top:0;
left:0;
width:100px;
height:40px;
}
.file_input_wrap label{
width:100%;
height:100%;
display:block;
opacity:0;
cursor:pointer;
}
.file_input_wrap input{
opacity:0;
filter:alpha(opacity=0);/*ie8及以下*/
position:absolute;
top:7px;
right:173px;
cursor:pointer;
width:95px;
}
.photo_box .icon_pos{
height:20px;
width:20px;
display:block;
position:absolute;
right:0;
bottom:0;
}
.photo_box .loading{
height:10px;
display:block;
position:absolute;
left:0;
bottom:0;
background-image:url(loading.gif);
}
.sucess_icon{
background-image:url(icons_01.png);
background-position:0 0;
}
.error_icon{
background-image:url(icons_01.png);
background-position:-20px 0;
}
</style>
</head>
<body>
<div class="btns">
<a class="btn btn_add_pic" id="J_add_pic" href="javascript:;">添加图片</a>
<div class="file_input_wrap">
<input type="file" id="file" name="file" accept="image/*" multiple onChange="fileInfo(this)" />
<label id="J_add_area"></label>
</div>
</div>
<a class="btn btn_upload" id="J_upload" href="javascript:;">开始上传</a>
<div id="J_photo_wrap">
<ul class="photo_wrap">
</ul>
</div>
</body>
<script type="text/javascript" src="jquery-1.7.2.min.js"></script>
<script type="text/javascript">
var img_index = new Array();
function upload_img(){
var j=0;
img();
function img(){
//1.创建XMLHTTPRequest对象
if (img_index.length > 0){
var singleImg = img_index[j];
var xmlhttp;
if (window.XMLHttpRequest) {
//IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest;
//针对某些特定版本的mozillar浏览器的bug进行修正
if (xmlhttp.overrideMimeType) {
xmlhttp.overrideMimeType('text/xml');
};
} else if (window.ActiveXObject){
//IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
};
if(xmlhttp.upload){
//进度条
xmlhttp.upload.addEventListener("progress",
function(e) {
if (e.lengthComputable) {
var load_percent = (e.loaded / e.total) * 100;
$('#J_photo_wrap ul li').eq(j).find('.loading').css('width',load_percent+'%');
}
},
false);
//2.回调函数
//onreadystatechange是每次 readyState 属性改变的时候调用的事件句柄函数
xmlhttp.onreadystatechange = function(e){
if(xmlhttp.readyState==4){
if(xmlhttp.status==200){
var json = eval('(' + xmlhttp.responseText + ')');
if(json.status == 1){
$('#J_photo_wrap ul li').eq(j).find('.upload_result').text(singleImg.name+'上传完成');
$('#J_photo_wrap ul li').eq(j).find('.loading').hide();
$('#J_photo_wrap ul li').eq(j).find('.icon_pos').addClass('sucess_icon');
}else{
$('#J_photo_wrap ul li').eq(j).find('.upload_result').text(singleImg.name+'上传失败');
$('#J_photo_wrap ul li').eq(j).find('.loading').hide();
$('#J_photo_wrap ul li').eq(j).find('.icon_pos').addClass('error_icon');
}
}else{
$('#J_photo_wrap ul li').eq(j).find('.upload_result').text(singleImg.name+'上传失败');
$('#J_photo_wrap ul li').eq(j).find('.loading').hide();
$('#J_photo_wrap ul li').eq(j).find('.icon_pos').addClass('error_icon');
}
if (j < img_index.length - 1) {
j++;
img();
}
}
};
//3.设置连接信息
//初始化HTTP请求参数，但是并不发送请求。
//第一个参数连接方式，第二是url地址,第三个true是异步连接，默认是异步
//使用post方式发送数据
xmlhttp.open("POST","upload.php",true);
//4.发送数据，开始和服务器进行交互
//发送 HTTP 请求，使用传递给 open() 方法的参数，以及传递给该方法的可选请求中如果true, send这句话会立即执行
//如果是false（同步），send会在服务器数据回来才执行
//get方法在send中不需要内容
var formdata = new FormData();
formdata.append("FileData", singleImg);
xmlhttp.send(formdata);
}
//}
}
}
};
$('#J_upload').click(function(){
upload_img();
});
$('#J_add_area').hover(
function(){
$('#J_add_pic').addClass('btn_cur');
},
function(){
$('#J_add_pic').removeClass('btn_cur');
}
);
$('#J_add_area').click(function(){
$('#file').click();
});
function resize(img){
if(img.offsetHeight>img.offsetWidth){
$(img).removeClass('img1').addClass('img2');
}else{
$(img).removeClass('img2').addClass('img1');
}
}
function fileInfo(source){
var ireg = /image\/.*/i;
var files = source.files;
var name,size,type;
for(var i = 0, f; f = files[i]; i++) {
name = f.name;
size = f.size;
type = f.type;
if(!type.match(ireg)) {
$('#J_photo_wrap ul').append('<li><div class="photo_box">'+name+'不是图片<span class="loading"></span><span class="icon_pos"></span></div><div class="upload_result"></div></div></li>');
}else{
img_index.push(f);
if(size>1048576){
$('#J_photo_wrap ul').append('<li><div class="photo_box">'+name+'太大，无法生成预览<span class="loading"></span><span class="icon_pos"></span></div><div class="upload_result"></div></li>');
}else{
if(window.FileReader) {
var fr = new FileReader();
fr.onload = (function(f) {
return function(e){
$('#J_photo_wrap ul').append('<li><div class="photo_box"><img onload="resize(this);" src="'+this.result+'"/><span class="loading"></span><span class="icon_pos"></span></div><div class="upload_result"></div></li>');
};
})(f);
fr.readAsDataURL(f);
}
}
}
}
};
</script>
</html>
php收到文件的代码（这里只获取文件名字、类型、大小，没有进行其它操作）
<?php
$name = $_FILES['FileData']['name'];
$type = $_FILES['FileData']['type'];
$size = $_FILES['FileData']['size'];
$return = array (
"name" => $name,
"type" => $type,
"size" => $size,
"status" => 1
);
$return = json_encode($return);
echo $return;
?>
存在的问题
1、为了生成缩略图，readAsDataURL读取文件内容会占用内存，所以大图片会造成浏览器卡住或者奔溃
2、上传没有进行分段处理