unset form submit button
<body>
<?php
if(isset($_POST['vendor_add_submit'])){
//INSERT INTO DB
unset( $_POST['vendor_add_submit'] );
}
?>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'] ?>" >
<label>Email</label>
<input type="text" name="vendor_email" value="" />
<input type="submit" name="vendor_add_submit" value="SAVE" />
</form>
</body>
unset( $_POST['vendor_add_submit'] ); is used to prevent more than one time insertion into db on page refresh. I tested with print_r($_POST['vendor_add_submit'开发者_运维问答] ) before and after the unset and found that the unset() function does not work.
How can I achieve the purpose of the unset function, plz?
Unset isn't going to stop the refresh from being able to replay the POSTed data to the script. The unset function eliminated it for the remaining execution of that script, but a refresh is a fresh execution.
You could simply re-direct the browser to the entry pageafter doing your insert, that way a subsequent refresh will be safe.
//INSERT INTO DB
//...
header('Location: samepage.php');
exit();
I'm sure there are other ways to accomplish this as well.
Your approach cannot work, you would just be editing the data that the PHP script has recieved. If the user refreshes the browser then it will submit the same data again, and PHP will populate a fresh new $_POST with the data the browser sent.
If you want to stop a refresh resubmitting the data, then use the POST-REDIRECT-GET pattern.
The $_POST value will only be removed on the Server-Side Meaning that on that one request PHP will not be able to see or use it (You removed it).
But you are rendering the Submit button on the page's HTML so every time someone visits the page and submit the form they will submit the value again. And you will remove it again for PHP on that current request. So every request would insert the data into the database.
You might want to rather look into rather checking if the record already does exists (OR if the user has one already, not sure what you want) and then redirect them away from the page using header('Location: otherpage.php');.
Hope that helps...
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