这篇“Ajax怎么实现上传图像功能”文章的知识点大部分人都不太理解，所以小编给大家总结了以下内容，内容详细，步骤清晰，具有一定的借鉴价值，希望大家阅读完这篇文章能有所收获，下面我们一起来看看这篇“Ajax怎么实现上传图像功能”文章吧。
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" > <div class="progress-bar progress-bar-striped active" 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>以上就是关于“Ajax怎么实现上传图像功能”这篇文章的内容，相信大家都有了一定的了解，希望小编分享的内容对大家有帮助，若想了解更多相关的知识内容，请关注编程网行业资讯频道。
