Validating user input in html
Also, the attribute can be added to form controls, to programmatically indicate that they are required.
Most current web browsers support this attribute and will communicate missing required input to the user, using standard web browser dialog mechanisms.
Input Validation is the outer defensive perimeter for your web application.
If they click the input, it will activate the input. It's basically the secret selector for testing if an input currently has a value or not.
There is no IE or Firefox support though, which is particularly difficult to navigate around.
Beyond the perimeter is everything considered potential enemy territory which is...literally everything other than the literal code executed by the current request.
All possible entrances and exits on the perimeter are guarded day and night by trigger happy sentries who prefer to shoot first and never ask questions.
I'd say if the form is short and an obvious pattern (like sign up or log in), you could use the placeholder visual pattern, but use real labels instead. You don't need to do any tricky cursor stuff, because it's all semantically wired up already. In order to do that, we'll need to know if the input is empty or not.