javascript - How does front-end js encapsulate a method or a jQuery plug-in to enable clicking a button to open the local file management system and upload files?

Question

To execute an event after clicking a button, open the local file management system, then select the file, and then select upload

Answer 1

A method encapsulated some time ago, using ajax and formData methods to implement file upload and display the upload progress during the upload process

js

       $('#upload').on('click',function(){

            var xhr = new XMLHttpRequest();

            xhr.open('post','../PHP/post_file.php',true);

            // 获取上传进度
            xhr.upload.onprogress = (ev)=>{
                var scale = Math.round( (ev.loaded/ev.total)*100 );
                $('.text').html( scale + '%');
                $('.progress').css('width', scale + '%');
            };

            xhr.onload = ()=>{
                console.log('上传成功');
            };

            // 通过file表单的files属性拿到文件数据 通过formData将数据转换为二进制格式
            var fileInfo = new FormData();
            fileInfo.append( 'file',$('#iptFile')[0].files[0] );

            // 发送数据
            xhr.send(fileInfo);

        });

html

    <form action="">
        <input type="file" id="iptFile">
        <input type="button" id="upload" value="点击上传"/>
    </form>

    <p class="box">
        <p class="progress"></p>
        <p class="text">
            0%
        </p>
    </p>

css

        .box{
            position: relative;
            width: 400px;
            height: 50px;
            border:1px solid #000;
            margin-top:30px;
        }
        .progress{
            width: 0%;
            height: 100%;
            background-color: red;
        }
        .text{
            position: absolute;
            left: 0;
            top: 0;
            width: 100%;
            height: 100%;
            text-align: center;
        }

php (php is not written by me)

<?php
header('Content-type:text/html; charset="utf-8"');
$upload_dir = 'uploads/';

if(strtolower($_SERVER['REQUEST_METHOD']) != 'post'){
    exit_status(array('code'=>1,'msg'=>'错误提交方式'));
}

if(array_key_exists('file',$_FILES) && $_FILES['file']['error'] == 0 ){
    
    $pic = $_FILES['file'];
    
    if(move_uploaded_file($pic['tmp_name'], $upload_dir.$pic['name'])){
        exit_status(array('code'=>0,'msg'=>'上传成功','url'=>$upload_dir.$pic['name']));
    }
    
}
echo $_FILES['file']['error'];
exit_status(array('code'=>1,'msg'=>'出现了一些错误'));

function exit_status($str){
    echo json_encode($str);
    exit;
}
?>


需要在服务器环境下运行，我用的是wamp,上传的文件会存到和php同级下的uploads文件夹中
    

Answer 2

I just encountered a problem with uploading images on the front end two days ago. This article is my record. See if it helps. Portal

Answer 3

You can use <input type="file" /> to achieve this, and then change the input style through css