How to check if the form is submitted in JavaScript?
You should use the form's onsubmit event. It sounds like you are listening on the submit button's click event which isn't right. The form's submit event will only fire if the form is valid. The HTML5 validation rules will prevent this event from firing if the form is invalid.
How do I check my form submission?
Use isset() method in PHP to test the form is submitted successfully or not. In the code, use isset() function to check $_POST['submit'] method. Remember in place of submit define the name of submit button. After clicking on submit button this action will work as POST method.