Display progress bar when uploading files using JS-JS Tutorial-php.cn

Display progress bar when uploading files using JS

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Release： 2018-04-17 15:34:51

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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>

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<?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);

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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!