I have sầu a form on one page that submits lớn another page. There, it checks if the đầu vào mail is filled. If so then bởi vì something & if it is not filled, vì chưng something else. I don"t underst& why it always says that it is phối, even if I sover an empty form. What is missing or wrong?


<đầu vào type="password" name="password"/>

step2_kiểm tra.php:

if (isset($_POST<"mail">)) else
All text-lượt thích inputs and textareas present in your khung will be submitted khổng lồ the hệ thống even if their values are empty strings. – hypeJunction May 26 "16 at 9:28

Most khung inputs are always mix, even if not filled up, so you must kiểm tra for the emptiness too.

Bạn đang xem: If isset _post php

Since !empty() is already checks for both, you can use this:

if (!empty($_POST<"mail">)) else
This comparison table is very helpful for things like this php.net/manual/en/types.comparisons.php – A Star Jun 4 "13 at 22:16

Minor thing... I think it's preferable to lớn avoid the ! operator in cases like this (easier lớn read, less chance of error, etc.) & reverse the ngắn gọn xúc tích... if (empty()) else – MrWhite Aug 1 "14 at 10:58
I don't see why it would be preferrable to lớn avoid !empty(). I will admit, though, that I prefer lớn write failing conditions before successful conditions. – mickmackusa Mar 12 at 15:01

Use !empty instead of isphối. ismix return true for $_POST because $_POST array is superglobal và always exists (set).

Or better use $_SERVER<"REQUEST_METHOD"> == "POST"

You should mention that use BOTH isphối và !empty to prsự kiện error. EDIT: Whoops, it does apparently Learning every day then Ref – Touki Oct 24 "12 at 8:19

I tried and both works fine. Why is $_SERVER<'REQUEST_METHOD'> == 'POST' better? What does it exactly do? can it refers to lớn a specific đầu vào or it is generic to the form? – Nrc Oct 24 "12 at 8:55

$_SERVER<'REQUEST_METHOD'> ensures user has submitted form. $_POST can be empty even in this case. Consider this form:
, submitting it will sover nothing khổng lồ the action, but request type will be post. Or it can be done with curl: curl -X POST http://example.com/processor.php. If processor contains code lượt thích emang lại $_SERVER<'REQUEST_METHOD'>. ' '.var_export(empty($_POST),1);, you will see POST true – Nemoden Oct 25 "12 at 1:28
isset() can be appropriate when you specify a key within $_POST AND want to lớn allow a falsey value like 0. Particular to gmail value submissions, using !empty() is an inadequate tool to lớn validate an gmail address. – mickmackusa Mar 12 at 15:04

From php.net, isphối

Returns TRUE if var exists & has value other than NULL, FALSE otherwise.

empty space is considered as phối. You need lớn use empty() for checking all null options.

I find "for checking all null options" khổng lồ be either too vague or misleading to lớn researchers. – mickmackusa Mar 12 at 15:06

If you sover the khung empty, $_POST<"mail"> will still be sent, but the value is empty. To kiểm tra if the field is empty you need lớn check

if(isset($_POST<"mail">) && trim($_POST<"mail">) != "")
I copy paste the code & I think it does not work? Have you kiểm tra it? – Nrc Oct 24 "12 at 9:35
For the record, if(isset($_POST<"mail">) && trim($_POST<"mail">))

Alternatively, use empty()

if(!empty($_POST<"username">) and !empty($_POST<"password">))
According with the PHPhường type comparison tables you are absolutely right. A simple boolean does the work of the empty function to kiểm tra the empty string. – viery365 Dec 7 "17 at 21:44
I know this is old answer but first method can cause undefined index notice. – ICE Nov 28 "18 at 0:57

$_POST<'username'>. Thank you for noticing that. – Pedro Lobilớn Nov 28 "18 at 1:09
often makes code look unprofessional. Handle notices và warnings properly. – mickmackusa Mar 12 at 15:đôi mươi

Use !empty() instead of isset(). Because isset() will always return true in your case.

Xem thêm: Tải Game Aikatsu ! For Android, Tải Về Aikatsu! Apk Cho Android

if (!empty($_POST<"mail">)) else

Add the following attribute lớn the input text form: required="required". If the khung is not filled, it will not allow the user khổng lồ submit the form.

Your new code will be:

<đầu vào type="text" name="mail" required="required"/>

if (isset($_POST<"mail">))
Relying on client-side validation is not enough. It is trivial lớn manually circumvent client-side defenses. For improved security, svào validations need lớn be implemented on the server-side. As stated elsewhere on this page isset() will not work as required by the OPhường. – mickmackusa Mar 12 at 15:09
I totally agree. Wrote this answer a long baông chồng. This answer suggests the frontover side of things. Ideally validation should be done both in the frontover and the backend with error passing from VPS side và handling the error on the frontover. – Kushan Mehta Mar 13 at 17:05
Bottomline to researchers: this answer's server-side check does not ensure that the khung field is filled in. – mickmackusa Mar 13 at 20:45
This is more simply written as !empty(). It also makes your snippet less intuitive by checking for not zero on an email field's value. – mickmackusa Mar 15 at 10:59
You should explain why your code answers the OP's question. – Markus Nov 10 "17 at 7:46
As well as why you bởi vì not simply recommend !empty(). – mickmackusa Mar 12 at 11:00

Lets Think this is your HTML Form in step2.php


I think you need it for your database, so you can assign your HTML Form Value to lớn php Variable, now you can use Real Escape String và below must be your


if(isset($_POST<"mail">) && !empty($_POST<"mail">))

Where $db is your Database Connection.

isset() followed by !empty() is an antipattern that should not exist in any code for any reason. It is doing too much work. If !empty() is the desired ngắn gọn xúc tích, then also checking isset() is pointless. Also, vị not use mysqli_real_escape_string anymore; use prepared statements. – mickmackusa Mar 15 at 11:00

Check lớn see if the FORM has been submitted first, then the field. You should also sanitize the field khổng lồ prsự kiện hackers.

size name="new user" method="post" action="step2_kiểm tra.php">


if (isset($_POST<"SubmitForm">)) }
See how you are unconditionally declaring $Thư điện tử before checking if it is not empty? This is doing unnecessary work. !empty() does two things. It checks if a variable is declared & checks if it is truthy. Since the variable is certainly declared, you can just use if ($Email) else } else emang đến "Was there a problem: ".$errMess."!";
empty() is doing too much work here because $foo is guaranteed lớn be declared when it is checked. – mickmackusa Mar 15 at 10:57
You need khổng lồ explain your answer. SO exists lớn not just answer questions but to educate people – Machavity♦ Sep 29 "15 at 19:56
This answer does not check that the submitted email is not gmail. – mickmackusa Mar 15 at 10:53

<đầu vào type="password" name="password" required="required"/>
<đầu vào type="submit" value="continue"/> )) else ?>
This advice was given years earlier obatambeienwasirherbal.com/a/13045314/2943403 và adds no new value lớn the page. – mickmackusa Mar 15 at 10:52
This answer does not validate that $_POST<"mail"> is non-empty. – mickmackusa Mar 15 at 10:50

$-POST METHOD: if we use POST method in the khung tag lớn pass data,we can find data in the hệ thống using $_POST array.using this array name we fetch data from VPS.($_POST<"name">)Information sent from a khung with the POST method is invisible khổng lồ others(all names/values are embedded within the body of the HTTP. request) & has no limits n the amount of information khổng lồ sover. Example Code:

)) } else?>
Not only does this answer ignore the OP's scenario, this answer does nothing lớn kiểm tra if a field is "filled". – mickmackusa Mar 15 at 10:56

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