$(document).ready( function (){
    $("[id*='txtAddress1S']").blur(function() {
        var pattern = new RegExp('b[P|p]*(OST|ost)*.*s*[O|o|0]*(ffice|FFICE)*.*s*[B|b][O|o|0][X|x]b');
        if ($("[id*='txtAddress1S']").val().match(pattern)) {
            alert('We are unable to ship to a Post Office Box.nPlease provide a different shipping address.');
        }

    });
});

var pattern = new RegExp('\b[P|p]*(OST|ost)*\.*\s*[O|o|0]*(ffice|FFICE)*\.*\s*[B|b][O|o|0][X|x]\b');

var pattern = new RegExp('\b[p]*(ost)*\.*\s*[o|0]*(ffice)*\.*\s*b[o|0]x\b', 'i');

var pattern = new RegExp('[PO.]*\s?B(ox)?.*\d+', 'i');

var poBox = /^ *((#d+)|((box|bin)[-. /\]?d+)|(.*p[ .]? ?(o|0)[-. /\]? *-?((box|bin)|b|(#|num)?d+))|(p(ost)? *(o(ff(ice)?)?)? *((box|bin)|b)? *d+)|(p *-?/?(o)? *-?box)|post office box|((box|bin)|b) *(number|num|#)? *d+|(num|number|#) *d+)/i;

var matches = [ //"box" can be substituted for "bin"
    "#123",
    "Box 123",
    "Box-122",
    "Box122",
    "HC73 P.O. Box 217",
    "P O Box125",
    "P. O. Box",
    "P.O 123",
    "P.O. Box 123",
    "P.O. Box",
    "P.O.B 123",
    "P.O.B. 123",
    "P.O.B.",
    "P0 Box",
    "PO 123",
    "PO Box N",
    "PO Box",
    "PO-Box",
    "POB 123",
    "POB",
    "POBOX123",
    "Po Box",
    "Post 123",
    "Post Box 123",
    "Post Office Box 123",
    "Post Office Box",
    "box #123",
    "box 122",
    "box 123",
    "number 123",
    "p box",
    "p-o box",
    "p-o-box",
    "p.o box",
    "p.o. box",
    "p.o.-box",
    "p.o.b. #123",
    "p.o.b.",
    "p/o box",
    "po #123",
    "po box 123",
    "po box",
    "po num123",
    "po-box",
    "pobox",
    "pobox123",
    "post office box"
];

var nonMatches = [
    "The Postal Road",
    "Box Hill",
    "123 Some Street",
    "Controller's Office",
    "pollo St.",
    "123 box canyon rd",
    "777 Post Oak Blvd",
    "PSC 477 Box 396",
    "RR 1 Box 1020"
];

var pattern = /b(?:p.?s*o.?|posts+office)s+boxb/i;

var pattern = /bP(ost|ostal)?([ .]*(O|0)(ffice)?)?([ .]*Box)?b/i;

$pattern = '!p(ost)?.?s*o(ffice)?.?(box|s|$)!i';

var poRegex = /bP(ost|ostal)?([ .]*O(ffice)?)?([ .]*Box)?b/i;