Ajax实现上传图像功能的示例详解
时间：2022-07-27 11:18:06|栏目：JavaScript代码|点击： 次
最终效果展示
xhr发起请求
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="external nofollow" >
<script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
<!--1、文件选择框 -->
<input type="file" id="file1">
<!-- 2、上传文件的按钮 -->
<button id="btnupload">上传文件</button>
<br/>
<div class="progress" style="width:300px;margin:5px;">
<div class="progress-bar progress-bar-striped active" style="width: 0%;" id="precent">
0%
</div>
</div>
<!-- 3、img标签 来显示上传成功以后的图片 -->
<img alt="" id="img" width="800">
<script>
var precent = document.querySelector('#precent')
var btnupload = document.querySelector('#btnupload')
btnupload.addEventListener('click', function() {
var files = document.querySelector('#file1').files
if (files.length <= 0) {
return alert('请选择要上传的文件')
}
var fd = new FormData()
fd.append('avatar', files[0])
var xhr = new XMLHttpRequest()
xhr.upload.onprogress = function(e) {
console.log(e);
if (e.lengthComputable) {
var h = Math.ceil((e.loaded / e.total) * 100)
precent.style.width = h + '%'
precent.innerHTML = h + '%'
console.log(h);
}
}
xhr.upload.onload = function() {
$('#precent').removeClass().addClass('progress-bar progress-bar-success')
}
xhr.open('post', 'http://www.liulongbin.top:3006/api/upload/avatar')
xhr.send(fd)
xhr.onreadystatechange = function() {
if (xhr.readyState == 4 && xhr.status == 200) {
var data = JSON.parse(xhr.responseText)
console.log(data);
if (data.status == 200) {
console.log('上传成功');
document.querySelector('#img').src = 'http://www.liulongbin.top:3006' + data.url
} else {
console.log('上传失败');
}
}
}
})
</script>
</body>
</html>
ajax发起请求
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="jquery.js"></script>
<style>
img {
width: 50px;
height: 50px;
display: none;
}
</style>
</head>
<body>
<input type="file" id="file1">
<button id="btnupload">上传文件</button>
</br>
<img src="5-121204193R5-50.gif" alt="" id="loading">
<script>
$(function() {
$(document).ajaxStart(function() {
$('#loading').show()
})
$(document).ajaxStop(function() {
$('#loading').hide()
})
$('#btnupload').on('click', function() {
var files = $('#file1')[0].files
if (files.length <= 0) {
alert('请选择文件')
}
console.log('ok');
var fd = new FormData()
fd.append('avatar', files[0])
$.ajax({
method: 'POST',
url: 'http://www.liulongbin.top:3006/api/upload/avatar',
data: fd,
processData: false,
contentType: false,
success: function(res) {
console.log(res);
}
})
})
})
</script>
</body>
</html>
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本文标题：Ajax实现上传图像功能的示例详解
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