<html><body>$txt1 = "Hello";$txt2 = " world!";$txt1 .= $txt2;echo $txt1; </body><!-- Mirrored from www.w3schools.com/php/phptryit.asp?filename=tryphp_oper_string2 by HTTrack Website Copier/3.x [XR&CO'2014], Mon, 27 Jan 2020 02:29:31 GMT --></html>