Determine the difference between if($_POST[submit]) and if(isset($_POST[submit])) when submitting a form in PHP_PHP Tutorial

This should be used if(isset($_POST['submit'])) {
}
The difference between if($_POST[submit]) and if(isset($_POST[submit])) when submitting a form

The first method will cause a warning, while the second method is relatively more rigorous.
Also, it is best to add single quotes to the POST key name, so that the efficiency is slightly higher (about 3-4 times).
Well, it almost means that. If this variable is set, it returns true

What does if(isset($_POST['Submit'])) mean in PHP?
isset -- Check whether the variable is set

Determine whether the posted data has been submitted

Copy the code The code is as follows:

if(isset ($_POST["submit"]){
echo "submit is no come~";
}else
{
echo "submit is no come~";
}

http://www.bkjia.com/PHPjc/322948.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/322948.htmlTechArticle should be used like this if(isset($_POST['submit'])) { } when submitting the form if($ The difference between _POST[submit]) and if(isset($_POST[submit])) The first method will cause a warning, the second method is relatively more rigorous...