Problem of registration page

I made a page for the registration of accounts, with checks on the fields is the client side than server side, but I have a small problem.

For controls the client side I receive the alert directly to the page registration, while for the server-side controls made in php I open a blank page by typing the message written in the command echo.

Is there a way to do something similar to controls on the client side server side controls? Let me see the error on the same page, so the user is forced to turn back.

What you want is a very common procedure of AJAX environments.

If you want to avoid that language, simply create an invisible iframe within your page. Then just send the form to that iframe and PHP receives the data telling him to create the JavaScript that displays the message style "alert" that you need if the form is incorrect, or the same way, please refresh the page if the form is correct.

Perhaps it is difficult to describe, but in practice it is very simple.

I will try to do it in AJAX although in the rest of the site I did not use it? AJAX is somewhat difficult to me. I am aware of the fact that it is good enough for websites but never got 100% success in its usage. Just wish me a luck.

Import an AJAX framework only for what is feasible but it seems very optimal.
Rather you can see some single command Asynchronous JavaScript and use that which is not difficult and you will find many examples on google.

I decided to try to do it anyway because AJAX seeing what can be done will be useful later in the actual creation of the site.

I see what I can combine then and if I have any problem I will come back to ask you all experts ...