PHP数组通过foreach进行验证

I am doing a tutorial on PHP. I am in the update section of the CRUD lesson and am working on a validation script. I have followed the code exactly... I think but still not working correctly. Here is the problem: When I click submit to try to test the validation with the menu name field empty it goes through without an error... and updates the nav with an empty list item? I have looked over the code and all seems to be correct but I am very new to this so problems are easily overlooked. I am doing a tutorial on PHP. I am in the updat