使用我的PHP，我试图检查页面加载，如果用户点击提交（到达那里）或只是加载页面，但如果他们刚刚加载我得到一个错误[关闭]

Question

I'm checking it with if ($_POST["submit"]) but of course if they didn't, it's trying to access a variable that doesn't exist. However, I was using this check to see if it did exist in the first place, but PHP outputs the error for me.

Is that... okay? I'm not doing anything with it, I'm just checking if it's there. Or is there a better way to do it?

Same thing with my radio buttons. If they hit submit I check to see their values, but if they hit submit without pressing any I get an error.

Answer 1

You'll want to use isset for that:

if ( isset($_POST["submit"]) )

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A better way would be to just check the REQUEST_METHOD, to see if it's a POST request:

if ( $_SERVER['REQUEST_METHOD') == 'POST' )