Three steps to upload a picture in PHP

1. Uploading a picture three steps

The first step : First determine whether the file type is a picture format, if you upload files;

The second step : And then rename the file (generally to avoid uploading the file name, and now basically is the time to be named);

The third step : Finally upload the file to the specified directory, successfully uploaded after the output upload image preview.

2. Code (1) Determine whether the file type is a picture type

1 <? PHP 2 function type () {3     return substr (strrchr($HTTP _post_files[' file '] [' name '], '. '), 1); 4 }5 ?>

Description

1. STRRCHR: Finds the position of the last occurrence of a string in another string and returns all characters from that position to the end of the string.
2. SUBSTR: Takes a partial string.
3. $HTTP _post_files[' file ' [' name ']: Gets the full name of the file currently being uploaded.

(2) If the picture, upload the file, and then rename the file according to the time

1  if(!in_arry (Strtolower(Type ()),$type)){  2     $text=implode(‘.‘,$type); 3     Echo"You can only upload the following types of files:",$text, "<br>"; 4}Else{5     $filename=Explode(".",$_files[' UserFile '] [' name ']);//put the uploaded file name as "." Number to make an array. 6     $time=Date("M-d-h-i-s");//to the current upload time7     $filename[0]=$time;//take file name T replace8Name=implode(".",$filename);//the file name after uploading9     $uploadfile=$uploaddir.$name;//the file name address after uploadingTen}

This step is also divided into three steps:

First, write an array of types that can be uploaded, $type=array("JPG", "gif", "BMP", "JPEG", "PNG");

Then, judge the legitimacy of the document;

Finally, duplicate the file name.

Description

• Strtolower: Converts all the letters of a string to lowercase letters.
• In_array: The function searches the array for the given value.
• Implode: function combines array elements into a single string
• Random: Randomly generated numbers
• $_files[' UserFile ' [' name ']: Upload file name
• $uploaddir: A variable that you define yourself. For example, in the same folder, you want to put the uploaded files in this folder in the file folder, you can define $uploaddir="./file/"; Note the wording

• $_files["File" ["Name"]-the name of the file being uploaded
• $_files["File" ["type"]-the type of file being uploaded
• $_files["File" ["Size"]-the size of the uploaded file, measured in bytes
• $_files["File" ["Tmp_name"]-the name of the temporary copy of the file stored on the server
• $_files["File" ["Error"]-error code caused by file upload

(3) Finally upload the file to the specified directory, the upload Image preview after successful uploading

1 if(Move_uploaded_file($_files[' UserFile '] [' Tmp_name '],$uploadfile)){2     Echo"<center> your file has been uploaded upload picture preview: </center><br><center>$uploadfile' ></center> '; 3     Echo"<br><center><a href= ' Javascrīpt:history.go ( -1) ' > Continue uploading </a></center>"; 4}Else{5     Echo"Transmission failed!" "; 6}

The move_uploaded_file () function is a PHP system function that moves uploaded files to a new location.

Syntax: move_uploaded_file(file, Newloc)

Note : This function is only used for files uploaded via HTTP POST.

Note : If the destination file already exists, it will be overwritten.

Also attached:w3school php File Upload

Three steps to upload a picture in PHP