Laravel link a controller function using xmlhtpp.open

I am new to laravel 5 and I want to know how can I use xmlhttp.open to send a GET request.

Here is what supposed to be my javascript code:

xmlhttp.open("GET", "reg_validation?field=" + field + "&query=" + query, false);

So how can I link that one to a function inside a controller and return its value with xmlhttp.responseText

via Chebli Mohamed