Detailed explanation of PHP avatar upload preview example

This article mainly introduces the detailed example of PHP avatar upload preview. Interested friends can refer to it. I hope it will be helpful to everyone.

Speaking of uploading pictures, everyone is familiar with it. However, in future projects, you may not be allowed to upload pictures using the submit refresh page method. For example, uploading avatars, according to common sense, must be in the photo album. After selecting the photo, confirm the upload, and it will definitely not be uploaded through the form, click submit to refresh the upload. I will introduce to you two types of asynchronous non-refresh uploading of pictures. Picture preview: The first one is uploaded through the ready-made uploadfy plug-in. There are many examples on the Internet.

But what I will focus on introducing to you is the second method, uploading images through Ajax. Because using the uploadfy plug-in requires the device to support Flash in swf format, the first method cannot be used for most mobile phones. First, let me tell you about the uploading principle: control the file text field through js. After selecting the photo, submit the form asynchronously through Ajax, then use the position of the picture as the return value, and use js to set the src attribute of the img as the return value. .

Upload avatar area:

Code:

         
    上传头像   
 
 
 
  ×  
 上传头像 
 
 
 
  
  
 
  
 
 关闭   
 
 
 
   

Upload processing page:

alert('该文件已存在！');"; } else { move_uploaded_file($_FILES["file"]["tmp_name"],$filename); unlink($_POST["tp"]); echo ""; } } }

Principle:

Put the file temporarily into the tmp directory in the wamp folder through the enctype="multipart/form-data" attribute of the form form, and then pass it through the background The php program saves the file in the system.

The above is the entire content of this article, I hope it will be helpful to everyone's study.

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