app/assets/javascripts/url.js
A1.replaceUrlParam = function(url, paramName, paramValue)
{
if (paramValue == null) {
paramValue = '';
}
var pattern = new RegExp('\\b('+paramName+'=).*?(&|#|$)');
if (url.search(pattern)>=0) {
return url.replace(pattern,'$1' + paramValue + '$2');
}
url = url.replace(/[?#]$/,'');
return url + (url.indexOf('?')>0 ? '&' : '?') + paramName + '=' + paramValue;
}