<section class="upload-section">
<article class="upload-piclist">
<div class="upload-file">
<input type="file" id="file" accept="image/*" multiple onchange="imgChange()"/>
</div>
</article>
</section>
css:
/* body {
margin: 0
padding: 0
max-width: 414px
margin: 0 auto
} */
.upload-fh {
background-image: url('data:image/pngbase64,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')
background-repeat: no-repeat
background-size: 100% 100%
height: 30px
width: 30px
}
.upload-hedaer {
height: 55px
display: grid
grid-template-columns: repeat(3, 1fr)
padding: 0 10px
box-sizing: border-box
align-items: center
text-align: center
background: #287cff
color: #fff
border-bottom: 1px solid #efefef
font-size: 19px
}
.upload-hedaer div:last-child {
text-align: right
}
.upload-textarea {
width: 100%
height: 60px
font-size: 28px
border: 1px solid #efefee
max-height: 300px
}
.upload-article-text {
width: 100%
padding: 10px
box-sizing: border-box
}
.upload-file {
position: relative
background: url('../images/z_add.png') no-repeat 50%/100% 100%
/* width: 100px*/
height: 120px
order: 9
}
.upload-piclist {
padding: 0 10px
box-sizing: border-box
display: grid
grid-template-columns: repeat(3, 120px)
justify-content: space-between
grid-gap: 14px
}
#file {
width: 100%
height: 100%
opacity: 0
}
.upload-Picitem {
width: 100%
height: 120px
}
.upload-Picitem>img {
width: 100%
height: 100%
object-fit: cover
}
.submit {
padding: 15px 0
background-color: #287cff
color: #fff
text-align: center
margin: 10px
font-size: 20px
border-radius: 10px
}
.upload-sm {
padding: 10px
box-sizing: border-box
color: gray
}
.upload-sm ol>li {
margin-bottom: 10px
}
js:let picmax = 9//限制上传数量
function imgChange() {
let file = document.getElementById('file').files
let imglist = document.querySelectorAll('.upload-Picitem')
let piclist = document.getElementsByClassName('upload-piclist')[0]
let filelist = file.length + imglist.length >picmax ? 9 - imglist.length : file.length + imglist.length
if (file.length + imglist.length >= 9) {
let uploadfile = document.getElementsByClassName('upload-file')[0]
uploadfile.style.display = "none"
}
for (let i = 0i <filelisti++) {
readerfile(file[i]).then(e =>{
let html = document.createElement('div')
html.className = 'upload-Picitem'
html.innerHTML = '<img src=' + e + ' alt="pic">'
piclist.appendChild(html)
})
}
}
function readerfile(file) {
return new Promise((resolve, reject) =>{
let reader = new FileReader()
reader.addEventListener("load", function() {
resolve(reader.result)
}, false)
if (file) {
reader.readAsDataURL(file)
}
})
}
//提交
function submit() {
let imglist = []
let text = document.getElementsByClassName('upload-textarea')[0].value
let piclist = document.querySelectorAll('.upload-Picitem')
for (let i = 0i <piclist.lengthi++) {
imglist.push(piclist[i].lastChild.src)
}
console.log("发布内容：", text)
console.log("图片列表：", imglist)
}
//textarea高度自适应
var autoTextarea = function(elem, extra, maxHeight) {
extra = extra || 0
var isFirefox = !!document.getBoxObjectFor || 'mozInnerScreenX' in window,
isOpera = !!window.opera &&!!window.opera.toString().indexOf('Opera'),
addEvent = function(type, callback) {
elem.addEventListener ?
elem.addEventListener(type, callback, false) :
elem.attachEvent('on' + type, callback)
},
getStyle = elem.currentStyle ? function(name) {
var val = elem.currentStyle[name]
if (name === 'height' &&val.search(/px/i) !== 1) {
var rect = elem.getBoundingClientRect()
return rect.bottom - rect.top -
parseFloat(getStyle('paddingTop')) -
parseFloat(getStyle('paddingBottom')) + 'px'
}
return val
} : function(name) {
return getComputedStyle(elem, null)[name]
},
minHeight = parseFloat(getStyle('height'))
elem.style.resize = 'none'
var change = function() {
var scrollTop, height,
padding = 0,
style = elem.style
if (elem._length === elem.value.length) return
elem._length = elem.value.length
if (!isFirefox &&!isOpera) {
padding = parseInt(getStyle('paddingTop')) + parseInt(getStyle('paddingBottom'))
}
scrollTop = document.body.scrollTop || document.documentElement.scrollTop
elem.style.height = minHeight + 'px'
if (elem.scrollHeight >minHeight) {
if (maxHeight &&elem.scrollHeight >maxHeight) {
height = maxHeight - padding
style.overflowY = 'auto'
} else {
height = elem.scrollHeight - padding
style.overflowY = 'hidden'
}
style.height = height + extra + 'px'
scrollTop += parseInt(style.height) - elem.currHeight
document.body.scrollTop = scrollTop
document.documentElement.scrollTop = scrollTop
elem.currHeight = parseInt(style.height)
}
}
// addEvent('propertychange', change)
// addEvent('input', change)
// addEvent('focus', change)
change()
}
pic:z_add.png
在HTML标准中，XMLHttpRequest对象被重新定义，被称为“XMLHttpRequest Level 2”，其中包含了以下5个新特性：
1、支持上传、下载字节流，比如文件、blob以及表单数据。
2、增加了上传、下载中的进度事件。
3、跨域请求的支持。
4、允许发送匿名请求（即不发送HTTP的Referer部分）。
5、允许设置请求的超时。
在这篇教程中，我们主要关注第一和第二项特性，尤其是第二项——它能够提供我们想要的上传进度。和之前的方案不同，这个方案并不要求服务器作出特殊的设置，因此大家边看教程就可以边动手试试了。
上面图示的就是我们能够实现的内容：
1、显示上传的文件信息，比如文件名、类型、尺寸。
2、一个能够显示真实进度的进度条。
3、上传的速度。
4、剩余时间的估算。
5、已上传的数据量。
6、上传结束后服务器返回的响应。
另外，凭借XMLHttpRequest，我们的上传过程整个都是异步的，因此用户在上传文件的时候，依然可以操作网页当中的其它元素，并不需要专门等待上传的完成。而在上传结束后，我们能够获取服务器发回的响应，因此整个上传过程都显得相当顺理成章。
