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Display progress bar when uploading files using JS

php中世界最好的语言Original: 2018-04-17 15:34:511742browse

This time I will bring you the progress bar displayed when uploading files with JS. What are the precautions for displaying the progress bar when uploading files with JS? The following is a practical case. Let’s take a look. one time.

Modify the required size in php.ini:

upload_max_filesize = 8M
post_max_size = 10M
memory_limit = 20M

<!DOCTYPE html>
<html>
<head>
  <title>原生JS大文件显示进度条</title>
  <meta charset="UTF-8">
  <style type="text/css">
    #parent{position: relative;width: 500px;height:20px;border:1px solid #ccc;display: none;border-radius:20px}
    #child{position: absolute;width:0%;height:20px;background: #5FB878;display: none;line-height: 20px;color: #ffffff;font-size: 12px;border-radius:20px}
  </style>
  <script type="text/javascript">
    function $(id){
      return document.getElementById(id);
    }
  </script>
</head>
<body>
  <form action="" method="post">
    <p id="parent">
      <p id="child"></p>
    </p>
    <p>上传文件:<input type="file" name="file"></p>  
    <p><input type="submit" value="提交" id="submit"></p>
  </form>
  <script type="text/javascript">
    var oForm = document.getElementsByTagName('form')[0];
    var oSubmit = $('submit');
    //如果多个人同时提交这个表单的时候，由于是异步的请求，互不影响
    oSubmit.onclick = function(){
      try{
        var xhr = new XMLHttpRequest();
      }catch(e){
        var xhr = new ActiveXObject("Msxml2.XMLHTTP");
      }
      xhr.upload.onprogress = function(e){
        var ev = e || window.event;
        var percent = Math.floor((ev.loaded / ev.total)*100);    
        // console.log(percent);
        //将百分比显示到进度条
        $('parent').style.display = 'block';
        $('child').style.display = 'block';
        //将上传进度的百分比显示到child里面
        $('child').style.width = percent+'%';
        $('child').style.textAlign = 'center';
        $('child').innerHTML = percent+'%';
        //判断如果百分比到达100%时候，隐藏掉
        if(percent==100){
          $('parent').style.display = 'none';
          $('child').style.display = 'none';
        }
      }
      xhr.open('post','progress.php',true);
      var form = new FormData(oForm);
      xhr.send(form);
      xhr.onreadystatechange = function(){
        if(xhr.readyState==4 && xhr.status==200){
          eval("var obj ="+xhr.responseText);
          if(obj.status){
            alert('上传成功');
          }else{
            alert('上传失败');
          }
        }
      }
      //阻止表单提交
      return false;
    }
  </script>
</body>
</html>

<?php
  //开始上传
  //注意：文件是windows系统的文件，采用的gbk编码，php文件使用的是utf-8编码
  //我们不能直接修改文件的编码，只能临时修改一下php的编码
  $dst_file = $_FILES['file']['name'];
  $dst_file = iconv('utf-8', 'gbk', $dst_file);
  if(move_uploaded_file($_FILES['file']['tmp_name'],$dst_file)){
    $data['status'] = 1;
  }else{
    $data['status'] = 0;
  }
  echo json_encode($data);

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

Display progress bar when uploading files using JS

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