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How to implement image upload preview in PHP?

Guanhui
GuanhuiOriginal
2020-07-21 15:12:553894browse

How to implement image upload preview in PHP?

PHP How to implement image upload preview?

First listen to the onchange event of the input tag; then use AJAX to upload the file to the server; then receive the uploaded file in PHP and save the file; finally return the file access path, and Just use JS to render.

Sample code

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>上传头像</title>
<style type="text/css">
  *{
    font-family:"微软雅黑";}
  #zong{
    /*border:1px solid black;*/
    position:relative;
    width:52%;
    height:500x;
    left:24%}
  .nr{
    float:left;
    margin-right:30px;}
  #yl{width:240px; height:240px; background-size:240px 240px;}
  #file{width:240px; height:240px; float:left; opacity:0;}
</style>
</head>

<body>

<div id="zong">
<form id="sc" action="2.php" method="post" enctype="multipart/form-data" target="shangchuan">
  
  <input type="hidden" name="tp" value="" id="tp" />
  
  <div id="yl" style="background-image:url(./image/1.jpg)" class="nr">//头像显示的位置
    <input type="file" name="file" id="file" onchange="document.getElementById(&#39;sc&#39;).submit()" />
  </div>
  <div class="nr">
  </div> 
</form>

<iframe style="display:none" name="shangchuan" id="shangchuan">
</iframe>

</div>
</body>

<script type="text/javascript">

//回调函数,调用该方法传一个文件路径,改变背景图
function showimg(url)
{
  var div = document.getElementById("yl");
  div.style.backgroundImage = "url("+url+")";
  
  document.getElementById("tp").value = url;
}

</script>

</html>
<?php
session_start();
$uid = $_SESSION["uid"];
if($_FILES["file"]["error"])
{
  echo $_FILES["file"]["error"];
}
else
{
  if(($_FILES["file"]["type"]=="image/jpeg" || $_FILES["file"]["type"]=="image/png")&& $_FILES["file"]["size"]<1024000)
  {
    $fname = "./a/image/".date("YmdHis").$_FILES["file"]["name"];  //头像存储的路径
    
    $filename = iconv("UTF-8","gb2312",$fname);
    
    if(file_exists($filename))
    {
      echo "<script>alert(&#39;该文件已存在!&#39;);</script>";
    }
    else
    {
      move_uploaded_file($_FILES["file"]["tmp_name"],$filename);
      
      unlink($_POST["tp"]);
      echo "<script>parent.showimg(&#39;{$fname}&#39;);</script>";
    }
    
  }
}

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