在表单提交之前定义$ _POST变量[重复]

Question

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• Notice: Undefined index [duplicate] 4 answers

How can I define my $_POST variables in below sample code before submission to prevent PHP Undefined index notice. HTML sample code:

<form action="" method="post">
<input type="text" name="my_input" id="my_input">
<button type="submit">Submit</button>
</form>

my php sample code:

$post_variable = $_POST["my_input"];

Thanks in advance.

</div>

Answer 1

just check that the post variable exists before trying to access it:

$value1 = isset($_POST["my_input"]) ? $_POST['my_input'] : false;

now, if my_input is set in the post $value1 will contain it, otherwise it will be false