[Mobile Upload] jQuery cannot upload files to the php background while passing data-php Tutorial

Dear elders, this problem has been bothering me for a long time. [this is my previous question] (ask. csdn. netquestions231374 & quot;), an incomplete source code I downloaded online: the front-end has an upload box. after uploading an image, a preview image is automatically generated, however, the post or file methods on the php page in the background cannot receive the uploaded files, and text data can be received. Some great gods told me that using the form. js plug-in would not help the younger brother, so please tell me the detailed operation. Where can I add anything? The code is as follows :! [Front-end] (img. ask. csd php mobile jquery

Dear elders, this problem has plagued me for a long time. This is my previous question. I downloaded an incomplete source code from the Internet: The front-end has an upload box, after an image is uploaded, a preview image is automatically generated. However, the post or file methods on the php page in the background cannot receive the uploaded files, and text data can be received. Some great gods told me that using the form. js plug-in would not help the younger brother, so please tell me the detailed operation. Where can I add anything? The code is as follows:

Html code