PHP checks whether a file has been selected in the file box

PHP checks whether a file has been selected in the file box

Single Form

The Code is as follows:

<Form action = "? "Method =" post "enctype = 'multipart/form-data'> File Upload: <input type = "file" name = "file" id = "file"/> <Input type = "submit" id = "send" value = "submit"/> </Form> <? Php // Determine whether a file has been selected in the pic file box If (! Empty ($ _ FILES ['file'] ['tmp _ name']) { Echo 'selected files '; } Else { Echo 'select A file '; } // PS: ['tmp _ name'] After $ _ FILES must not be forgotten. It indicates a temporary meaning. ?>

Of course, you can use JS to determine the method as follows:

The Code is as follows:
<Script> Var send = document. getElementById ("send "); Send. onclick = function (){ Var file = document. getElementById ("file"). value; If (file. length <1 ){ Alert ('select the image '); Return false; } } </Script>

<Input type = "file" name = "uploadfile" contentEditable = "false" style = "width: 80%">

There are multiple forms,

When submitting a form, you must determine that at least one input file has been selected.

The Code is as follows:

<Input type = "file" name = "uploadfile" contentEditable = "false" style = "width: 80%"> <br> <Input type = "file" name = "uploadfile" contentEditable = "false" style = "width: 80%"> <br> <Input type = "file" name = "uploadfile" contentEditable = "false" style = "width: 80%"> <br> <Input type = "file" name = "uploadfile" contentEditable = "false" style = "width: 80%"> <br> <Input type = "file" name = "uploadfile" contentEditable = "false" style = "width: 80%">

Use jQuery to judge:

The Code is as follows:
Var fileFlag = false; $ ("Input [name = 'uploadfile']"). each (function (){ If ($ (this). val ()! = ""){ Fileflag = true; Return false; } }); If (fileFlag ){ Alert ("selected files already exist "); }

As long as the fileFlag is true, you can exit the each loop and do not need to judge the remaining input.

Use return false in each to exit the loop. Use return true to end the current loop and perform the next loop.