( function() {

function queryStringConstructor() {

this.params = {};

var qs = location.search.substring(1, location.search.length),

i = 0,

args;

if (qs.length > 0) {

// Turn <plus> back to <space>

// See:

// http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13.4.1

qs = qs.replace(/\+/g, ' ');

// parse out name/value pairs separated via &

args = qs.split('&');

// split out each name=value pair

for ( i = 0; i < args.length; i = i + 1) {

var pair = args[i].split('=');

var name = decodeURIComponent(pair[0]);

var value = (pair.length === 2) ? decodeURIComponent(pair[1]) : null;

this.params[name] = value;

}

}

return this;

}

function parseQueryString() {

return new queryStringConstructor(arguments);

}

queryStringConstructor.prototype = {

getValue : function(key, defaultText) {

var value = this.params[key];

return (value !== null) ? value : defaultText;

},

contains : function(key) {

var value = this.params[key];

return (value !== null);

},

getKeys : function() {

var keys = [],

key;

for ( key in this.params) {

keys.push(key);

}

return keys;

}

}

window.parseQueryString = parseQueryString;

})();