Make a title of the field goes over the field: asp MVC/Razor

Question

Hi,

I want when I enters information in the field, then the title of the field goes over the field.

Here is my code:

 

so in the field we have the text "FIRSTNAME", my purpose is when i enters information in this field, the text "FIRSTNAME" goes over the field.

And as long as the client has nothing to enter in a field, then the title remains in the field.

I search a lot if there is a trick to add in TextBoxFor to do that but i didn't find!

 

state initial : 

 

state final: 

 

Thanks a lot 

 

@Html.TextBoxFor(model => model.FirstName, new { @placeholder = "FIRSTNAME", @class = "adresse-input"})