Online PHP editor | refs for bpNIR

<?php function check_tcno($tcno) { preg_replace('/([1-9]{1})([0-9]{1})([0-9]{1})([0-9]{1})([0-9]{1})([0-9]{1})([0-9]{1})([0-9]{1})([0-9]{1}).*$/e', "eval('\$on=((((\\1+\\3+\\5+\\7+\\9)*7)-(\\2+\\4+\\6+\\8))%10); \$onbir=(\\1+\\2+\\3+\\4+\\5+\\6+\\7+\\8+\\9+\$on)%10; \$sonIki = \$on.\$onbir;')", $tcno); return(substr($tcno, -2) == $sonIki); }