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javascript - ajax upload file background uses $_files to accept empty

不言
不言Original
2018-05-16 09:49:002800browse

javascript code: 

<html><head><meta charset="UTF-8">
<style>
img{
   max-width:80%;
   display:block;
}
</style>
</head><body><input id="img" type="file">
<p id="text"></p>
<script>
var 
up=function(o,success,x,file){
   if(typeof success==&#39;function&#39;)
   file=o;
   x=new XMLHttpRequest()
   x.open(&#39;POST&#39;,&#39;http://127.0.0.1/up.php?r=&#39;+Math.random(),1)

   x.onload=function(r){
       r=x.responseText
       if(success)//if r.pid and the twice parameter existing
           return success(r)
   }
   x.send(file)
}
</script>
<script>
img.onchange=function(){
   if(!this.files||!this.files[0])
       return alert(&#39;选取文件出错！&#39;)

   var 
   imgfile=this.files[0]

   if(imgfile.type.indexOf(&#39;image&#39;)!=0)
       return alert(&#39;这不是一个图像或音频！&#39;)
   
   up(imgfile,function(r){
       text.innerHTML=r

   })
}
</script>
</body>
</html>

Backend code: 

<?php
  header(&#39;Access-Control-Allow-Origin:*&#39;);
  header("Content-Type:text/json;charset=utf-8");
  echo json_encode($_FILES); 
  ?>

The return data is []

Reply content:

javascript code: 

<html><head><meta charset="UTF-8">
<style>
img{
   max-width:80%;
   display:block;
}
</style>
</head><body><input id="img" type="file">
<p id="text"></p>
<script>
var 
up=function(o,success,x,file){
   if(typeof success==&#39;function&#39;)
   file=o;
   x=new XMLHttpRequest()
   x.open(&#39;POST&#39;,&#39;http://127.0.0.1/up.php?r=&#39;+Math.random(),1)

   x.onload=function(r){
       r=x.responseText
       if(success)//if r.pid and the twice parameter existing
           return success(r)
   }
   x.send(file)
}
</script>
<script>
img.onchange=function(){
   if(!this.files||!this.files[0])
       return alert(&#39;选取文件出错！&#39;)

   var 
   imgfile=this.files[0]

   if(imgfile.type.indexOf(&#39;image&#39;)!=0)
       return alert(&#39;这不是一个图像或音频！&#39;)
   
   up(imgfile,function(r){
       text.innerHTML=r

   })
}
</script>
</body>
</html>

Backend code: 

 <?php
  header(&#39;Access-Control-Allow-Origin:*&#39;);
  header("Content-Type:text/json;charset=utf-8");
  echo json_encode($_FILES); 
  ?>

The return data is []

Asynchronously upload files, you should use FormData. For example: 

var oMyForm = new FormData();
oMyForm.append("file", file);
x.send(oMyForm);


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