PHP: Print post data, return the issue with a length of not 1 but the content is empty

Problem:

First, the HTML looks like this:

We can see that the name value of the textarea tag is cten, so we check to see if the post is getting the data properly:

　　

Background to get:

　

Result: We can get the data normally

　　

Next, we make a judgment: to determine whether the user is empty, is empty, you are prompted that it cannot enter empty data, otherwise display the input data :

　　

We deliberately do not enter data :

Results:

As we can see, the system does not enter the IF statement judgment, but executes the code of Var_dump ($_post), and the displayed length is 21 instead of 1:

So this is why, since it is not the post reason that is the reason for the HTML, to see the HTML code, found that:

　　

Workaround:

　　

To submit the empty data again:

　　

Results:

When when, the problem solved, knock happy, thank the friend who gave me a hint!

END

PHP: Print post data, return the issue with a length of not 1 but the content is empty