javascript - How to turn function into jQuery plugin -

here's jsfiddle: http://jsfiddle.net/jsfiddleplayer/vhg7csb7/10/

i trying implement answer in stackoverflow question jquery plugin , having no luck. getparameterbyname function reads url's querystring variables , returns 1 indicated in argument. however, code keeps saying:

.getparameterbyname not function

my jquery code follows:

$(document).ready(function(){     var paramabc = $.getparameterbyname('abc');         alert(paramabc); });  (function ($) {     /* gets value of querystring variable name */     $.fn.getparameterbyname = function (name) {         name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");         var regex = new regexp("[\\?&]" + name + "=([^&#]*)"),             results = regex.exec(('http://www.myexample.com/?abc=1&def=2').search);         return results === null ? "" : decodeuricomponent(results[1].replace(/\+/g, " "));     }; }(jquery)); 

note i've hardcoded location in above function because jsfiddle doesn't have querystring variables on url. original code line was:

results = regex.exec(location.search); 

if code working, return 1 (because abc=1 in querystring) , display in alert(). doing wrong? thanks.

you there use $ instead of $.fn, $.fn alias prototype of jquery , expects selector

$.getparameterbyname = function (name) {    // }; 

note: define plugin code first use it.

a read what difference between $ , $.fn?

demo